diff --git a/example/geographic.cpp b/example/geographic.cpp
index a287d3f3..a6bc66d1 100644
--- a/example/geographic.cpp
+++ b/example/geographic.cpp
@@ -26,7 +26,7 @@
 
 namespace {
 
-using namespace units::isq::si::unit_constants;
+using namespace units::isq::si::references;
 inline constexpr auto earth_radius = 6371 * km;
 
 }  // namespace
diff --git a/example/glide_computer_example.cpp b/example/glide_computer_example.cpp
index 46533ab9..5f270738 100644
--- a/example/glide_computer_example.cpp
+++ b/example/glide_computer_example.cpp
@@ -31,7 +31,7 @@ using namespace glide_computer;
 
 auto get_gliders()
 {
-  using namespace si::unit_constants;
+  using namespace si::references;
 UNITS_DIAGNOSTIC_PUSH
 UNITS_DIAGNOSTIC_IGNORE_MISSING_BRACES
   static const std::array gliders = {
@@ -45,7 +45,7 @@ UNITS_DIAGNOSTIC_POP
 
 auto get_weather_conditions()
 {
-  using namespace si::unit_constants;
+  using namespace si::references;
   static const std::array weather_conditions = {
       std::pair("Good", weather{height(1900 * m), rate_of_climb(4.3 * m / s)}),
       std::pair("Medium", weather{height(1550 * m), rate_of_climb(2.8 * m / s)}),
@@ -56,7 +56,7 @@ auto get_weather_conditions()
 auto get_waypoints()
 {
   using namespace geographic::literals;
-  using namespace units::isq::si::international::unit_constants;
+  using namespace units::isq::si::international::references;
   static const std::array waypoints = {
       waypoint{"EPPR", {54.24772_N, 18.6745_E}, altitude(16 * ft)},    // N54°14'51.8" E18°40'28.2"
       waypoint{"EPGI", {53.52442_N, 18.84947_E}, altitude(115 * ft)}   // N53°31'27.9" E18°50'58.1"
@@ -140,7 +140,7 @@ void print(const aircraft_tow& tow)
 
 void example()
 {
-  using namespace si::unit_constants;
+  using namespace si::references;
 
   const safety sfty = {height(300 * m)};
   const auto gliders = get_gliders();
diff --git a/example/hello_units.cpp b/example/hello_units.cpp
index 3d45255e..92e58772 100644
--- a/example/hello_units.cpp
+++ b/example/hello_units.cpp
@@ -36,7 +36,7 @@ constexpr Speed auto avg_speed(Length auto d, Time auto t)
 int main()
 {
   using namespace units::isq::si::literals;
-  using namespace units::isq::si::unit_constants;
+  using namespace units::isq::si::references;
 
   constexpr Speed auto v1 = 110 * km / h;
   constexpr Speed auto v2 = avg_speed(220_q_km, 2_q_h);
diff --git a/src/core/include/units/generic/angle.h b/src/core/include/units/generic/angle.h
index 2bc549b7..f890df86 100644
--- a/src/core/include/units/generic/angle.h
+++ b/src/core/include/units/generic/angle.h
@@ -46,10 +46,10 @@ constexpr auto operator"" _q_rad(long double l) { return angle<radian, long doub
 
 }  // namespace literals
 
-inline namespace unit_constants {
+inline namespace references {
 
 inline constexpr auto rad = reference<dim_angle<>, radian>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units
diff --git a/src/core/include/units/reference.h b/src/core/include/units/reference.h
index d64d74b0..71e3e2e6 100644
--- a/src/core/include/units/reference.h
+++ b/src/core/include/units/reference.h
@@ -58,7 +58,7 @@ using reference_divide = detail::reference_divide_impl<
  * This type is intended to be used in the unit constants definition:
  *
  * @code{.cpp}
- * namespace unit_constants {
+ * namespace references {
  * 
  * inline constexpr auto m = reference<dim_length, metre>{};
  * inline constexpr auto km = reference<dim_length, kilometre>{};
@@ -69,7 +69,7 @@ using reference_divide = detail::reference_divide_impl<
  * Unit constants simplify quantity creation:
  * 
  * @code{.cpp}
- * using namespace units::isq::si::unit_constants;
+ * using namespace units::isq::si::references;
  *
  * auto d = 123 * m;
  * auto v = 70 * km / h;
diff --git a/src/systems/data/include/units/data/bitrate.h b/src/systems/data/include/units/data/bitrate.h
index 7338bb9a..5e871443 100644
--- a/src/systems/data/include/units/data/bitrate.h
+++ b/src/systems/data/include/units/data/bitrate.h
@@ -56,7 +56,7 @@ constexpr auto operator"" _q_Pib_per_s(unsigned long long l) { gsl_ExpectsAudit(
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto b_per_s = reference<dim_bitrate, bit_per_second>{};
 inline constexpr auto Kib_per_s = reference<dim_bitrate, kibibit_per_second>{};
@@ -65,6 +65,6 @@ inline constexpr auto Gib_per_s = reference<dim_bitrate, gibibit_per_second>{};
 inline constexpr auto Tib_per_s = reference<dim_bitrate, tebibit_per_second>{};
 inline constexpr auto Pib_per_s = reference<dim_bitrate, pebibit_per_second>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::data
diff --git a/src/systems/data/include/units/data/information.h b/src/systems/data/include/units/data/information.h
index eda46486..47de34a4 100644
--- a/src/systems/data/include/units/data/information.h
+++ b/src/systems/data/include/units/data/information.h
@@ -72,7 +72,7 @@ constexpr auto operator"" _q_PiB(unsigned long long l) { gsl_ExpectsAudit(std::i
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto b = reference<dim_information, bit>{};
 inline constexpr auto Kib = reference<dim_information, kibibit>{};
@@ -88,6 +88,6 @@ inline constexpr auto GiB = reference<dim_information, gibibyte>{};
 inline constexpr auto TiB = reference<dim_information, tebibyte>{};
 inline constexpr auto PiB = reference<dim_information, pebibyte>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::data
diff --git a/src/systems/si-cgs/include/units/isq/si/cgs/acceleration.h b/src/systems/si-cgs/include/units/isq/si/cgs/acceleration.h
index ac9f63ab..b6b8f950 100644
--- a/src/systems/si-cgs/include/units/isq/si/cgs/acceleration.h
+++ b/src/systems/si-cgs/include/units/isq/si/cgs/acceleration.h
@@ -42,10 +42,10 @@ constexpr auto operator"" _q_Gal(long double l) { return acceleration<gal, long
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto Gal = reference<dim_acceleration, gal>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::cgs
diff --git a/src/systems/si-cgs/include/units/isq/si/cgs/area.h b/src/systems/si-cgs/include/units/isq/si/cgs/area.h
index a92cd921..721635d9 100644
--- a/src/systems/si-cgs/include/units/isq/si/cgs/area.h
+++ b/src/systems/si-cgs/include/units/isq/si/cgs/area.h
@@ -43,10 +43,10 @@ constexpr auto operator"" _q_cm2(long double l) { return area<square_centimetre,
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto cm2 = reference<dim_area, square_centimetre>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::cgs
diff --git a/src/systems/si-cgs/include/units/isq/si/cgs/energy.h b/src/systems/si-cgs/include/units/isq/si/cgs/energy.h
index b877cbc9..dedcb008 100644
--- a/src/systems/si-cgs/include/units/isq/si/cgs/energy.h
+++ b/src/systems/si-cgs/include/units/isq/si/cgs/energy.h
@@ -44,10 +44,10 @@ constexpr auto operator"" _q_erg(long double l) { return energy<erg, long double
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto erg = reference<dim_energy, cgs::erg>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::cgs
diff --git a/src/systems/si-cgs/include/units/isq/si/cgs/force.h b/src/systems/si-cgs/include/units/isq/si/cgs/force.h
index 43359c39..bed1efec 100644
--- a/src/systems/si-cgs/include/units/isq/si/cgs/force.h
+++ b/src/systems/si-cgs/include/units/isq/si/cgs/force.h
@@ -45,10 +45,10 @@ constexpr auto operator"" _q_dyn(long double l) { return force<dyne, long double
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto dyn = reference<dim_force, dyne>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::cgs
diff --git a/src/systems/si-cgs/include/units/isq/si/cgs/length.h b/src/systems/si-cgs/include/units/isq/si/cgs/length.h
index 36e17615..5a72fa5b 100644
--- a/src/systems/si-cgs/include/units/isq/si/cgs/length.h
+++ b/src/systems/si-cgs/include/units/isq/si/cgs/length.h
@@ -42,10 +42,10 @@ constexpr auto operator"" _q_cm(long double l) { return length<centimetre, long
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto cm = reference<dim_length, centimetre>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::cgs
diff --git a/src/systems/si-cgs/include/units/isq/si/cgs/mass.h b/src/systems/si-cgs/include/units/isq/si/cgs/mass.h
index a69f9fb1..b82c4895 100644
--- a/src/systems/si-cgs/include/units/isq/si/cgs/mass.h
+++ b/src/systems/si-cgs/include/units/isq/si/cgs/mass.h
@@ -42,10 +42,10 @@ constexpr auto operator"" _q_g(long double l) { return mass<gram, long double>(l
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto g = reference<dim_mass, gram>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::cgs
diff --git a/src/systems/si-cgs/include/units/isq/si/cgs/pressure.h b/src/systems/si-cgs/include/units/isq/si/cgs/pressure.h
index f2f8ed9d..587b08c6 100644
--- a/src/systems/si-cgs/include/units/isq/si/cgs/pressure.h
+++ b/src/systems/si-cgs/include/units/isq/si/cgs/pressure.h
@@ -45,10 +45,10 @@ constexpr auto operator"" _q_Ba(long double l) { return pressure<barye, long dou
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto Ba = reference<dim_pressure, barye>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::cgs
diff --git a/src/systems/si-cgs/include/units/isq/si/cgs/time.h b/src/systems/si-cgs/include/units/isq/si/cgs/time.h
index bcb3e72f..9e2075ec 100644
--- a/src/systems/si-cgs/include/units/isq/si/cgs/time.h
+++ b/src/systems/si-cgs/include/units/isq/si/cgs/time.h
@@ -38,10 +38,10 @@ using si::literals::operator"" _q_s;
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
-using si::unit_constants::s;
+using si::references::s;
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::cgs
diff --git a/src/systems/si-fps/include/units/isq/si/fps/area.h b/src/systems/si-fps/include/units/isq/si/fps/area.h
index 082131fb..b933d124 100644
--- a/src/systems/si-fps/include/units/isq/si/fps/area.h
+++ b/src/systems/si-fps/include/units/isq/si/fps/area.h
@@ -43,10 +43,10 @@ constexpr auto operator"" _q_ft2(long double l) { return area<square_foot, long
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto ft2 = reference<dim_area, square_foot>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::fps
diff --git a/src/systems/si-fps/include/units/isq/si/fps/energy.h b/src/systems/si-fps/include/units/isq/si/fps/energy.h
index 136c5d10..b825dfac 100644
--- a/src/systems/si-fps/include/units/isq/si/fps/energy.h
+++ b/src/systems/si-fps/include/units/isq/si/fps/energy.h
@@ -55,11 +55,11 @@ constexpr auto operator"" _q_ft_lbf(long double l) { return energy<foot_pound_fo
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto ft_pdl = reference<dim_energy, foot_poundal>{};
 inline constexpr auto ft_lbf = reference<dim_energy, foot_pound_force>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::fps
diff --git a/src/systems/si-fps/include/units/isq/si/fps/force.h b/src/systems/si-fps/include/units/isq/si/fps/force.h
index 51af09c4..53e87241 100644
--- a/src/systems/si-fps/include/units/isq/si/fps/force.h
+++ b/src/systems/si-fps/include/units/isq/si/fps/force.h
@@ -62,12 +62,12 @@ constexpr auto operator"" _q_klbf(long double l) { return force<kilopound_force,
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto pdl = reference<dim_force, poundal>{};
 inline constexpr auto lbf = reference<dim_force, pound_force>{};
 inline constexpr auto klbf = reference<dim_force, kilopound_force>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::fps
diff --git a/src/systems/si-fps/include/units/isq/si/fps/length.h b/src/systems/si-fps/include/units/isq/si/fps/length.h
index e474fb12..91c436ec 100644
--- a/src/systems/si-fps/include/units/isq/si/fps/length.h
+++ b/src/systems/si-fps/include/units/isq/si/fps/length.h
@@ -93,7 +93,7 @@ constexpr auto operator"" _q_naut_mi(long double l) { return length<nautical_mil
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto thou = reference<dim_length, thousandth>{};
 inline constexpr auto mil = thou;
@@ -106,6 +106,6 @@ inline constexpr auto kyd = reference<dim_length, kiloyard>{};
 inline constexpr auto mile = reference<dim_length, fps::mile>{};
 inline constexpr auto naut_mi = reference<dim_length, nautical_mile>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::fps
diff --git a/src/systems/si-fps/include/units/isq/si/fps/mass.h b/src/systems/si-fps/include/units/isq/si/fps/mass.h
index 7402d88a..6e2f5100 100644
--- a/src/systems/si-fps/include/units/isq/si/fps/mass.h
+++ b/src/systems/si-fps/include/units/isq/si/fps/mass.h
@@ -91,7 +91,7 @@ constexpr auto operator"" _q_lton(long double l) { return mass<long_ton, long do
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto gr = reference<dim_mass, grain>{};
 inline constexpr auto dr = reference<dim_mass, dram>{};
@@ -103,6 +103,6 @@ inline constexpr auto cwt = reference<dim_mass, hundredweight>{};
 inline constexpr auto ston = reference<dim_mass, short_ton>{};
 inline constexpr auto lton = reference<dim_mass, long_ton>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::fps
diff --git a/src/systems/si-fps/include/units/isq/si/fps/power.h b/src/systems/si-fps/include/units/isq/si/fps/power.h
index a61ad406..21afbb3d 100644
--- a/src/systems/si-fps/include/units/isq/si/fps/power.h
+++ b/src/systems/si-fps/include/units/isq/si/fps/power.h
@@ -56,10 +56,10 @@ constexpr auto operator"" _q_hp(long double l) { return power<horse_power, long
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto hp = reference<dim_power, horse_power>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::fps
diff --git a/src/systems/si-fps/include/units/isq/si/fps/pressure.h b/src/systems/si-fps/include/units/isq/si/fps/pressure.h
index 174ed402..b9f8cdad 100644
--- a/src/systems/si-fps/include/units/isq/si/fps/pressure.h
+++ b/src/systems/si-fps/include/units/isq/si/fps/pressure.h
@@ -59,11 +59,11 @@ constexpr auto operator"" _q_kpsi(long double l) { return pressure<kilopound_for
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto psi = reference<dim_pressure, pound_force_per_inch_sq>{};
 inline constexpr auto kpsi = reference<dim_pressure, kilopound_force_per_inch_sq>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::fps
diff --git a/src/systems/si-fps/include/units/isq/si/fps/speed.h b/src/systems/si-fps/include/units/isq/si/fps/speed.h
index c2b3a961..275b9faa 100644
--- a/src/systems/si-fps/include/units/isq/si/fps/speed.h
+++ b/src/systems/si-fps/include/units/isq/si/fps/speed.h
@@ -58,11 +58,11 @@ constexpr auto operator"" _q_knot(long double l) { return speed<knot, long doubl
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto mph = reference<dim_speed, mile_per_hour>{};
 inline constexpr auto knot = reference<dim_speed, fps::knot>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::fps
diff --git a/src/systems/si-fps/include/units/isq/si/fps/time.h b/src/systems/si-fps/include/units/isq/si/fps/time.h
index 90738c4a..2ac1eeb6 100644
--- a/src/systems/si-fps/include/units/isq/si/fps/time.h
+++ b/src/systems/si-fps/include/units/isq/si/fps/time.h
@@ -40,10 +40,10 @@ using si::literals::operator"" _q_s;
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
-using si::unit_constants::s;
+using si::references::s;
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::fps
diff --git a/src/systems/si-fps/include/units/isq/si/fps/volume.h b/src/systems/si-fps/include/units/isq/si/fps/volume.h
index 5b4e8677..647a025c 100644
--- a/src/systems/si-fps/include/units/isq/si/fps/volume.h
+++ b/src/systems/si-fps/include/units/isq/si/fps/volume.h
@@ -48,11 +48,11 @@ constexpr auto operator"" _q_yd3(long double l) { return volume<cubic_yard, long
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto ft3 = reference<dim_volume, cubic_foot>{};
 inline constexpr auto yd3 = reference<dim_volume, cubic_yard>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::fps
diff --git a/src/systems/si-iau/include/units/isq/si/iau/length.h b/src/systems/si-iau/include/units/isq/si/iau/length.h
index b76e62cf..0970666f 100644
--- a/src/systems/si-iau/include/units/isq/si/iau/length.h
+++ b/src/systems/si-iau/include/units/isq/si/iau/length.h
@@ -52,12 +52,12 @@ constexpr auto operator"" _q_angstrom(long double l) { return si::length<angstro
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto ly = reference<si::dim_length, light_year>{};
 inline constexpr auto pc = reference<si::dim_length, parsec>{};
 inline constexpr auto angstrom = reference<si::dim_length, iau::angstrom>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::iau
diff --git a/src/systems/si-imperial/include/units/isq/si/imperial/length.h b/src/systems/si-imperial/include/units/isq/si/imperial/length.h
index a5e00204..d4d86056 100644
--- a/src/systems/si-imperial/include/units/isq/si/imperial/length.h
+++ b/src/systems/si-imperial/include/units/isq/si/imperial/length.h
@@ -44,11 +44,11 @@ constexpr auto operator"" _q_rd(long double l) { return si::length<rod, long dou
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto ch = reference<si::dim_length, chain>{};
 inline constexpr auto rd = reference<si::dim_length, rod>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::imperial
diff --git a/src/systems/si-international/include/units/isq/si/international/area.h b/src/systems/si-international/include/units/isq/si/international/area.h
index d6093505..5acfb01c 100644
--- a/src/systems/si-international/include/units/isq/si/international/area.h
+++ b/src/systems/si-international/include/units/isq/si/international/area.h
@@ -37,10 +37,10 @@ constexpr auto operator"" _q_ft2(long double l) { return si::area<square_foot, l
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto ft2 = reference<si::dim_area, square_foot>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::international
diff --git a/src/systems/si-international/include/units/isq/si/international/length.h b/src/systems/si-international/include/units/isq/si/international/length.h
index ea80c96d..c80f548a 100644
--- a/src/systems/si-international/include/units/isq/si/international/length.h
+++ b/src/systems/si-international/include/units/isq/si/international/length.h
@@ -94,7 +94,7 @@ constexpr auto operator"" _q_mil(long double l) { return si::length<mil, long do
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto yd = reference<si::dim_length, yard>{};
 inline constexpr auto ft = reference<si::dim_length, foot>{};
@@ -105,6 +105,6 @@ inline constexpr auto mi_naut = reference<si::dim_length, nautical_mile>{};
 inline constexpr auto thou = reference<si::dim_length, international::thou>{};
 inline constexpr auto mil = reference<si::dim_length, international::mil>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::international
diff --git a/src/systems/si-international/include/units/isq/si/international/volume.h b/src/systems/si-international/include/units/isq/si/international/volume.h
index 635627b2..320d7a03 100644
--- a/src/systems/si-international/include/units/isq/si/international/volume.h
+++ b/src/systems/si-international/include/units/isq/si/international/volume.h
@@ -37,10 +37,10 @@ constexpr auto operator"" _q_ft3(long double l) { return si::volume<cubic_foot,
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto ft3 = reference<si::dim_volume, cubic_foot>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::international
diff --git a/src/systems/si-typographic/include/units/isq/si/typographic/length.h b/src/systems/si-typographic/include/units/isq/si/typographic/length.h
index b16fa485..8c3fcaa9 100644
--- a/src/systems/si-typographic/include/units/isq/si/typographic/length.h
+++ b/src/systems/si-typographic/include/units/isq/si/typographic/length.h
@@ -53,13 +53,13 @@ constexpr auto operator"" _q_point_prn(long double l) { return si::length<point_
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto pica_comp = reference<si::dim_length, typographic::pica_comp>{};
 inline constexpr auto pica_prn = reference<si::dim_length, typographic::pica_prn>{};
 inline constexpr auto point_comp = reference<si::dim_length, typographic::point_comp>{};
 inline constexpr auto point_prn = reference<si::dim_length, typographic::point_prn>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::typographic
diff --git a/src/systems/si-us/include/units/isq/si/us/length.h b/src/systems/si-us/include/units/isq/si/us/length.h
index 4734e436..49b9489d 100644
--- a/src/systems/si-us/include/units/isq/si/us/length.h
+++ b/src/systems/si-us/include/units/isq/si/us/length.h
@@ -53,12 +53,12 @@ constexpr auto operator"" _q_mi_us(long double l) { return si::length<units::isq
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto ft = reference<si::dim_length, us::foot>{};
 inline constexpr auto fathom = reference<si::dim_length, us::fathom>{};
 inline constexpr auto mi = reference<si::dim_length, us::mile>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si::us
diff --git a/src/systems/si/include/units/isq/si/absorbed_dose.h b/src/systems/si/include/units/isq/si/absorbed_dose.h
index f46090d1..a050c3cf 100644
--- a/src/systems/si/include/units/isq/si/absorbed_dose.h
+++ b/src/systems/si/include/units/isq/si/absorbed_dose.h
@@ -144,7 +144,7 @@ constexpr auto operator"" _q_YGy(long double l) { return absorbed_dose<yottagray
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto Gy = reference<dim_absorbed_dose, gray>{};
 inline constexpr auto yGy = reference<dim_absorbed_dose, yoctogray>{};
@@ -168,6 +168,6 @@ inline constexpr auto EGy = reference<dim_absorbed_dose, exagray>{};
 inline constexpr auto ZGy = reference<dim_absorbed_dose, zettagray>{};
 inline constexpr auto YGy = reference<dim_absorbed_dose, yottagray>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/src/systems/si/include/units/isq/si/amount_of_substance.h b/src/systems/si/include/units/isq/si/amount_of_substance.h
index 29bfd03e..bed70765 100644
--- a/src/systems/si/include/units/isq/si/amount_of_substance.h
+++ b/src/systems/si/include/units/isq/si/amount_of_substance.h
@@ -44,10 +44,10 @@ constexpr auto operator"" _q_mol(long double l) { return amount_of_substance<mol
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto mol = reference<dim_amount_of_substance, mole>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/src/systems/si/include/units/isq/si/area.h b/src/systems/si/include/units/isq/si/area.h
index 6dc4032b..c5280666 100644
--- a/src/systems/si/include/units/isq/si/area.h
+++ b/src/systems/si/include/units/isq/si/area.h
@@ -149,7 +149,7 @@ constexpr auto operator"" _q_ha(long double l) { return area<hectare, long doubl
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto m2 = reference<dim_area, square_metre>{};
 inline constexpr auto ym2 = reference<dim_area, square_yoctometre>{};
@@ -174,6 +174,6 @@ inline constexpr auto Zm2 = reference<dim_area, square_zettametre>{};
 inline constexpr auto Ym2 = reference<dim_area, square_yottametre>{};
 inline constexpr auto ha = reference<dim_area, hectare>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/src/systems/si/include/units/isq/si/capacitance.h b/src/systems/si/include/units/isq/si/capacitance.h
index 3883d6f4..6ba72ea7 100644
--- a/src/systems/si/include/units/isq/si/capacitance.h
+++ b/src/systems/si/include/units/isq/si/capacitance.h
@@ -145,7 +145,7 @@ constexpr auto operator"" _q_YF(long double l) { return capacitance<yottafarad,
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto F = reference<dim_capacitance, farad>{};
 inline constexpr auto yF = reference<dim_capacitance, yoctofarad>{};
@@ -169,6 +169,6 @@ inline constexpr auto EF = reference<dim_capacitance, exafarad>{};
 inline constexpr auto ZF = reference<dim_capacitance, zettafarad>{};
 inline constexpr auto YF = reference<dim_capacitance, yottafarad>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/src/systems/si/include/units/isq/si/catalytic_activity.h b/src/systems/si/include/units/isq/si/catalytic_activity.h
index 6969ca11..9eea5965 100644
--- a/src/systems/si/include/units/isq/si/catalytic_activity.h
+++ b/src/systems/si/include/units/isq/si/catalytic_activity.h
@@ -151,7 +151,7 @@ constexpr auto operator"" _q_U(long double l) { return catalytic_activity<enzyme
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto kat = reference<dim_catalytic_activity, katal>{};
 inline constexpr auto ykat = reference<dim_catalytic_activity, yoctokatal>{};
@@ -176,7 +176,7 @@ inline constexpr auto Zkat = reference<dim_catalytic_activity, zettakatal>{};
 inline constexpr auto Ykat = reference<dim_catalytic_activity, yottakatal>{};
 inline constexpr auto U = reference<dim_catalytic_activity, enzyme_unit>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
 
diff --git a/src/systems/si/include/units/isq/si/conductance.h b/src/systems/si/include/units/isq/si/conductance.h
index 5df5f195..f9ddf04b 100644
--- a/src/systems/si/include/units/isq/si/conductance.h
+++ b/src/systems/si/include/units/isq/si/conductance.h
@@ -124,7 +124,7 @@ constexpr auto operator"" _q_YS(long double l) { return conductance<yottasiemens
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto S = reference<dim_conductance, siemens>{};
 inline constexpr auto yS = reference<dim_conductance, yoctosiemens>{};
@@ -144,7 +144,7 @@ inline constexpr auto ES = reference<dim_conductance, exasiemens>{};
 inline constexpr auto ZS = reference<dim_conductance, zettasiemens>{};
 inline constexpr auto YS = reference<dim_conductance, yottasiemens>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
 
diff --git a/src/systems/si/include/units/isq/si/dynamic_viscosity.h b/src/systems/si/include/units/isq/si/dynamic_viscosity.h
index 53c9f132..6fd2eb4c 100644
--- a/src/systems/si/include/units/isq/si/dynamic_viscosity.h
+++ b/src/systems/si/include/units/isq/si/dynamic_viscosity.h
@@ -43,11 +43,11 @@ constexpr auto operator"" _q_Pa_s(long double l) { return dynamic_viscosity<pasc
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto Pa_s = reference<dim_dynamic_viscosity, pascal_second>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
 
diff --git a/src/systems/si/include/units/isq/si/electric_charge.h b/src/systems/si/include/units/isq/si/electric_charge.h
index b755c530..e2866479 100644
--- a/src/systems/si/include/units/isq/si/electric_charge.h
+++ b/src/systems/si/include/units/isq/si/electric_charge.h
@@ -44,10 +44,10 @@ constexpr auto operator"" _q_C(long double l) { return electric_charge<coulomb,
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto C = reference<dim_electric_charge, coulomb>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/src/systems/si/include/units/isq/si/electric_current.h b/src/systems/si/include/units/isq/si/electric_current.h
index 671b9266..1cc34fd6 100644
--- a/src/systems/si/include/units/isq/si/electric_current.h
+++ b/src/systems/si/include/units/isq/si/electric_current.h
@@ -144,7 +144,7 @@ constexpr auto operator"" _q_YA(long double l) { return electric_current<yottaam
 
 } // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto A = reference<dim_electric_current, ampere>{};
 inline constexpr auto yA = reference<dim_electric_current, yoctoampere>{};
@@ -168,6 +168,6 @@ inline constexpr auto EA = reference<dim_electric_current, exaampere>{};
 inline constexpr auto ZA = reference<dim_electric_current, zettaampere>{};
 inline constexpr auto YA = reference<dim_electric_current, yottaampere>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/src/systems/si/include/units/isq/si/energy.h b/src/systems/si/include/units/isq/si/energy.h
index 88b22f2d..21a70f12 100644
--- a/src/systems/si/include/units/isq/si/energy.h
+++ b/src/systems/si/include/units/isq/si/energy.h
@@ -135,7 +135,7 @@ constexpr auto operator"" _q_GeV(long double l) { return energy<gigaelectronvolt
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto J = reference<dim_energy, joule>{};
 inline constexpr auto yJ = reference<dim_energy, yoctojoule>{};
@@ -157,6 +157,6 @@ inline constexpr auto YJ = reference<dim_energy, yottajoule>{};
 inline constexpr auto eV = reference<dim_energy, electronvolt>{};
 inline constexpr auto GeV = reference<dim_energy, gigaelectronvolt>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/src/systems/si/include/units/isq/si/force.h b/src/systems/si/include/units/isq/si/force.h
index be591827..9de0e6b3 100644
--- a/src/systems/si/include/units/isq/si/force.h
+++ b/src/systems/si/include/units/isq/si/force.h
@@ -145,7 +145,7 @@ constexpr auto operator"" _q_YN(long double l) { return force<yottanewton, long
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto N = reference<dim_force, newton>{};
 inline constexpr auto yN = reference<dim_force, yoctonewton>{};
@@ -169,6 +169,6 @@ inline constexpr auto EN = reference<dim_force, exanewton>{};
 inline constexpr auto ZN = reference<dim_force, zettanewton>{};
 inline constexpr auto YN = reference<dim_force, yottanewton>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/src/systems/si/include/units/isq/si/frequency.h b/src/systems/si/include/units/isq/si/frequency.h
index 538c6b27..b65c4682 100644
--- a/src/systems/si/include/units/isq/si/frequency.h
+++ b/src/systems/si/include/units/isq/si/frequency.h
@@ -123,7 +123,7 @@ constexpr auto operator"" _q_YHz(long double l) { return frequency<yottahertz, l
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto Hz = reference<dim_frequency, hertz>{};
 inline constexpr auto yHz = reference<dim_frequency, yoctohertz>{};
@@ -143,6 +143,6 @@ inline constexpr auto EHz = reference<dim_frequency, exahertz>{};
 inline constexpr auto ZHz = reference<dim_frequency, zettahertz>{};
 inline constexpr auto YHz = reference<dim_frequency, yottahertz>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/src/systems/si/include/units/isq/si/inductance.h b/src/systems/si/include/units/isq/si/inductance.h
index 7bfc48c8..8eeca3b9 100644
--- a/src/systems/si/include/units/isq/si/inductance.h
+++ b/src/systems/si/include/units/isq/si/inductance.h
@@ -125,7 +125,7 @@ constexpr auto operator"" _q_YH(long double l) { return inductance<yottahenry, l
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto H = reference<dim_inductance, henry>{};
 inline constexpr auto yH = reference<dim_inductance, yoctohenry>{};
@@ -145,6 +145,6 @@ inline constexpr auto EH = reference<dim_inductance, exahenry>{};
 inline constexpr auto ZH = reference<dim_inductance, zettahenry>{};
 inline constexpr auto YH = reference<dim_inductance, yottahenry>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/src/systems/si/include/units/isq/si/length.h b/src/systems/si/include/units/isq/si/length.h
index 273b17f3..152e9228 100644
--- a/src/systems/si/include/units/isq/si/length.h
+++ b/src/systems/si/include/units/isq/si/length.h
@@ -150,7 +150,7 @@ constexpr auto operator"" _q_au(long double l) { return length<astronomical_unit
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto m = reference<dim_length, metre>{};
 inline constexpr auto ym = reference<dim_length, yoctometre>{};
@@ -175,6 +175,6 @@ inline constexpr auto Zm = reference<dim_length, zettametre>{};
 inline constexpr auto Ym = reference<dim_length, yottametre>{};
 inline constexpr auto au = reference<dim_length, astronomical_unit>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/src/systems/si/include/units/isq/si/luminous_intensity.h b/src/systems/si/include/units/isq/si/luminous_intensity.h
index 7f94d82f..bee4716e 100644
--- a/src/systems/si/include/units/isq/si/luminous_intensity.h
+++ b/src/systems/si/include/units/isq/si/luminous_intensity.h
@@ -144,7 +144,7 @@ constexpr auto operator"" _q_Ycd(long double l) { return luminous_intensity<yott
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto cd = reference<dim_luminous_intensity, candela>{};
 inline constexpr auto ycd = reference<dim_luminous_intensity, yoctocandela>{};
@@ -168,6 +168,6 @@ inline constexpr auto Ecd = reference<dim_luminous_intensity, exacandela>{};
 inline constexpr auto Zcd = reference<dim_luminous_intensity, zettacandela>{};
 inline constexpr auto Ycd = reference<dim_luminous_intensity, yottacandela>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/src/systems/si/include/units/isq/si/magnetic_flux.h b/src/systems/si/include/units/isq/si/magnetic_flux.h
index b55ae82c..69a9e786 100644
--- a/src/systems/si/include/units/isq/si/magnetic_flux.h
+++ b/src/systems/si/include/units/isq/si/magnetic_flux.h
@@ -125,7 +125,7 @@ constexpr auto operator"" _q_YWb(long double l) { return magnetic_flux<yottawebe
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto Wb = reference<dim_magnetic_flux, weber>{};
 inline constexpr auto yWb = reference<dim_magnetic_flux, yoctoweber>{};
@@ -145,6 +145,6 @@ inline constexpr auto EWb = reference<dim_magnetic_flux, exaweber>{};
 inline constexpr auto ZWb = reference<dim_magnetic_flux, zettaweber>{};
 inline constexpr auto YWb = reference<dim_magnetic_flux, yottaweber>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/src/systems/si/include/units/isq/si/magnetic_induction.h b/src/systems/si/include/units/isq/si/magnetic_induction.h
index b391ee14..b2b5b152 100644
--- a/src/systems/si/include/units/isq/si/magnetic_induction.h
+++ b/src/systems/si/include/units/isq/si/magnetic_induction.h
@@ -133,7 +133,7 @@ constexpr auto operator"" _q_G(long double l) { return magnetic_induction<gauss,
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto T = reference<dim_magnetic_induction, tesla>{};
 inline constexpr auto yT = reference<dim_magnetic_induction, yoctotesla>{};
@@ -154,6 +154,6 @@ inline constexpr auto ZT = reference<dim_magnetic_induction, zettatesla>{};
 inline constexpr auto YT = reference<dim_magnetic_induction, yottatesla>{};
 inline constexpr auto G = reference<dim_magnetic_induction, gauss>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 } // namespace units
diff --git a/src/systems/si/include/units/isq/si/mass.h b/src/systems/si/include/units/isq/si/mass.h
index 9e3e1219..e31b7203 100644
--- a/src/systems/si/include/units/isq/si/mass.h
+++ b/src/systems/si/include/units/isq/si/mass.h
@@ -256,7 +256,7 @@ constexpr auto operator"" _q_Da(long double l) { return mass<dalton, long double
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto g = reference<dim_mass, gram>{};
 inline constexpr auto yg = reference<dim_mass, yoctogram>{};
@@ -302,6 +302,6 @@ inline constexpr auto Zt = reference<dim_mass, zettatonne>{};
 inline constexpr auto Yt = reference<dim_mass, yottatonne>{};
 inline constexpr auto Da = reference<dim_mass, dalton>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/src/systems/si/include/units/isq/si/power.h b/src/systems/si/include/units/isq/si/power.h
index e85bda02..c4e8d4df 100644
--- a/src/systems/si/include/units/isq/si/power.h
+++ b/src/systems/si/include/units/isq/si/power.h
@@ -124,7 +124,7 @@ constexpr auto operator"" _q_YW(long double l) { return power<yottawatt, long do
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto W = reference<dim_power, watt>{};
 inline constexpr auto yW = reference<dim_power, yoctowatt>{};
@@ -144,6 +144,6 @@ inline constexpr auto EW = reference<dim_power, exawatt>{};
 inline constexpr auto ZW = reference<dim_power, zettawatt>{};
 inline constexpr auto YW = reference<dim_power, yottawatt>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/src/systems/si/include/units/isq/si/pressure.h b/src/systems/si/include/units/isq/si/pressure.h
index 507edb01..904be115 100644
--- a/src/systems/si/include/units/isq/si/pressure.h
+++ b/src/systems/si/include/units/isq/si/pressure.h
@@ -145,7 +145,7 @@ constexpr auto operator"" _q_YPa(long double l) { return pressure<yottapascal, l
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto Pa = reference<dim_pressure, pascal>{};
 inline constexpr auto yPa = reference<dim_pressure, yoctopascal>{};
@@ -169,6 +169,6 @@ inline constexpr auto EPa = reference<dim_pressure, exapascal>{};
 inline constexpr auto ZPa = reference<dim_pressure, zettapascal>{};
 inline constexpr auto YPa = reference<dim_pressure, yottapascal>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/src/systems/si/include/units/isq/si/radioactivity.h b/src/systems/si/include/units/isq/si/radioactivity.h
index ee5440b8..47538e55 100644
--- a/src/systems/si/include/units/isq/si/radioactivity.h
+++ b/src/systems/si/include/units/isq/si/radioactivity.h
@@ -143,7 +143,7 @@ constexpr auto operator"" _q_YBq(long double l) { return radioactivity<yottabecq
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto Bq = reference<dim_radioactivity, becquerel>{};
 inline constexpr auto yBq = reference<dim_radioactivity, yoctobecquerel>{};
@@ -167,6 +167,6 @@ inline constexpr auto EBq = reference<dim_radioactivity, exabecquerel>{};
 inline constexpr auto ZBq = reference<dim_radioactivity, zettabecquerel>{};
 inline constexpr auto YBq = reference<dim_radioactivity, yottabecquerel>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/src/systems/si/include/units/isq/si/resistance.h b/src/systems/si/include/units/isq/si/resistance.h
index 6eab97b2..9253d90e 100644
--- a/src/systems/si/include/units/isq/si/resistance.h
+++ b/src/systems/si/include/units/isq/si/resistance.h
@@ -125,7 +125,7 @@ constexpr auto operator"" _q_YR(long double l) { return resistance<yottaohm, lon
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto R = reference<dim_resistance, ohm>{};
 inline constexpr auto yR = reference<dim_resistance, yoctoohm>{};
@@ -145,6 +145,6 @@ inline constexpr auto ER = reference<dim_resistance, exaohm>{};
 inline constexpr auto ZR = reference<dim_resistance, zettaohm>{};
 inline constexpr auto YR = reference<dim_resistance, yottaohm>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/src/systems/si/include/units/isq/si/thermodynamic_temperature.h b/src/systems/si/include/units/isq/si/thermodynamic_temperature.h
index 0a592dfe..0383ffe4 100644
--- a/src/systems/si/include/units/isq/si/thermodynamic_temperature.h
+++ b/src/systems/si/include/units/isq/si/thermodynamic_temperature.h
@@ -43,10 +43,10 @@ constexpr auto operator"" _q_K(long double l) { return thermodynamic_temperature
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto K = reference<dim_thermodynamic_temperature, kelvin>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/src/systems/si/include/units/isq/si/time.h b/src/systems/si/include/units/isq/si/time.h
index 78f1750a..91e73c80 100644
--- a/src/systems/si/include/units/isq/si/time.h
+++ b/src/systems/si/include/units/isq/si/time.h
@@ -99,7 +99,7 @@ constexpr auto operator"" _q_d(long double l) { return time<day, long double>(l)
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto ys = reference<dim_time, yoctosecond>{};
 inline constexpr auto zs = reference<dim_time, zeptosecond>{};
@@ -114,6 +114,6 @@ inline constexpr auto min = reference<dim_time, minute>{};
 inline constexpr auto h = reference<dim_time, hour>{};
 inline constexpr auto d = reference<dim_time, day>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/src/systems/si/include/units/isq/si/torque.h b/src/systems/si/include/units/isq/si/torque.h
index 49321b5a..59c4d904 100644
--- a/src/systems/si/include/units/isq/si/torque.h
+++ b/src/systems/si/include/units/isq/si/torque.h
@@ -45,10 +45,10 @@ constexpr auto operator"" _q_Nm_per_rad(long double l) { return torque<newton_me
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto Nm_per_rad = reference<dim_torque, newton_metre_per_radian>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/src/systems/si/include/units/isq/si/voltage.h b/src/systems/si/include/units/isq/si/voltage.h
index ea59b452..5a3ae49d 100644
--- a/src/systems/si/include/units/isq/si/voltage.h
+++ b/src/systems/si/include/units/isq/si/voltage.h
@@ -145,7 +145,7 @@ constexpr auto operator"" _q_YV(long double l) { return voltage<yottavolt, long
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto V = reference<dim_voltage, volt>{};
 inline constexpr auto yV = reference<dim_voltage, yoctovolt>{};
@@ -169,6 +169,6 @@ inline constexpr auto EV = reference<dim_voltage, exavolt>{};
 inline constexpr auto ZV = reference<dim_voltage, zettavolt>{};
 inline constexpr auto YV = reference<dim_voltage, yottavolt>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/src/systems/si/include/units/isq/si/volume.h b/src/systems/si/include/units/isq/si/volume.h
index 52dcf1a3..8eded6fd 100644
--- a/src/systems/si/include/units/isq/si/volume.h
+++ b/src/systems/si/include/units/isq/si/volume.h
@@ -249,7 +249,7 @@ constexpr auto operator"" _q_Yl(long double l) { return volume<yottalitre, long
 
 }  // namespace literals
 
-namespace unit_constants {
+namespace references {
 
 inline constexpr auto m3 = reference<dim_volume, cubic_metre>{};
 inline constexpr auto ym3 = reference<dim_volume, cubic_yoctometre>{};
@@ -294,6 +294,6 @@ inline constexpr auto El = reference<dim_volume, exalitre>{};
 inline constexpr auto Zl = reference<dim_volume, zettalitre>{};
 inline constexpr auto Yl = reference<dim_volume, yottalitre>{};
 
-}  // namespace unit_constants
+}  // namespace references
 
 }  // namespace units::isq::si
diff --git a/test/unit_test/static/quantity_kind_test.cpp b/test/unit_test/static/quantity_kind_test.cpp
index ed7addfb..75734c08 100644
--- a/test/unit_test/static/quantity_kind_test.cpp
+++ b/test/unit_test/static/quantity_kind_test.cpp
@@ -38,9 +38,9 @@ namespace {
 using namespace units;
 namespace si = isq::si;
 using namespace si;
-using namespace unit_constants;
+using namespace references;
 
-constexpr auto cgs_cm = cgs::unit_constants::cm;
+constexpr auto cgs_cm = cgs::references::cm;
 
 using namespace std::chrono_literals;
 
diff --git a/test/unit_test/static/quantity_point_kind_test.cpp b/test/unit_test/static/quantity_point_kind_test.cpp
index 73844e05..57670569 100644
--- a/test/unit_test/static/quantity_point_kind_test.cpp
+++ b/test/unit_test/static/quantity_point_kind_test.cpp
@@ -38,10 +38,10 @@ namespace {
 using namespace units;
 namespace si = isq::si;
 using namespace si;
-using namespace unit_constants;
+using namespace references;
 using sys_seconds = std::chrono::time_point<std::chrono::system_clock, std::chrono::seconds>;
 
-constexpr auto cgs_cm = cgs::unit_constants::cm;
+constexpr auto cgs_cm = cgs::references::cm;
 
 using namespace std::chrono_literals;
 
diff --git a/test/unit_test/static/quantity_point_test.cpp b/test/unit_test/static/quantity_point_test.cpp
index a597bba9..4034d998 100644
--- a/test/unit_test/static/quantity_point_test.cpp
+++ b/test/unit_test/static/quantity_point_test.cpp
@@ -34,7 +34,7 @@ namespace {
 
 using namespace units;
 using namespace isq::si;
-using namespace unit_constants;
+using namespace references;
 using namespace std::chrono_literals;
 using sys_seconds = std::chrono::time_point<std::chrono::system_clock, std::chrono::seconds>;
 
diff --git a/test/unit_test/static/quantity_test.cpp b/test/unit_test/static/quantity_test.cpp
index 1dd64367..b1adbac4 100644
--- a/test/unit_test/static/quantity_test.cpp
+++ b/test/unit_test/static/quantity_test.cpp
@@ -40,9 +40,9 @@ namespace {
 using namespace units;
 namespace si = isq::si;
 using namespace si;
-using namespace unit_constants;
+using namespace references;
 
-constexpr auto cgs_cm = cgs::unit_constants::cm;
+constexpr auto cgs_cm = cgs::references::cm;
 
 
 //////////////////////////////
diff --git a/test/unit_test/static/unit_constants.cpp b/test/unit_test/static/unit_constants.cpp
index 591bbf91..45e1e63f 100644
--- a/test/unit_test/static/unit_constants.cpp
+++ b/test/unit_test/static/unit_constants.cpp
@@ -39,7 +39,7 @@
 using namespace units;
 using namespace units::isq;
 using namespace units::isq::si;
-using namespace units::isq::si::unit_constants;
+using namespace units::isq::si::references;
 
 static_assert(2 * m == 2_q_m);
 static_assert(2 * s == 2_q_s);