diff --git a/example/kalman_filter/kalman_filter-example_1.cpp b/example/kalman_filter/kalman_filter-example_1.cpp
index 7ae4bce9..cf6f66f3 100644
--- a/example/kalman_filter/kalman_filter-example_1.cpp
+++ b/example/kalman_filter/kalman_filter-example_1.cpp
@@ -23,8 +23,8 @@
 #include "kalman.h"
 #include <units/isq/si/mass.h>
 #include <units/format.h>
+#include <units/generic/dimensionless.h>
 #include <array>
-#include <iostream>
 
 // Based on: https://www.kalmanfilter.net/alphabeta.html#ex1
 
diff --git a/example/kalman_filter/kalman_filter-example_2.cpp b/example/kalman_filter/kalman_filter-example_2.cpp
index e7679dae..759e8439 100644
--- a/example/kalman_filter/kalman_filter-example_2.cpp
+++ b/example/kalman_filter/kalman_filter-example_2.cpp
@@ -25,8 +25,8 @@
 #include <units/isq/si/speed.h>
 #include <units/isq/si/time.h>
 #include <units/format.h>
+#include <units/generic/dimensionless.h>
 #include <array>
-#include <iostream>
 
 // Based on: https://www.kalmanfilter.net/alphabeta.html#ex2
 
diff --git a/example/kalman_filter/kalman_filter-example_3.cpp b/example/kalman_filter/kalman_filter-example_3.cpp
index 3a8bf91d..16e9ff74 100644
--- a/example/kalman_filter/kalman_filter-example_3.cpp
+++ b/example/kalman_filter/kalman_filter-example_3.cpp
@@ -25,8 +25,8 @@
 #include <units/isq/si/speed.h>
 #include <units/isq/si/time.h>
 #include <units/format.h>
+#include <units/generic/dimensionless.h>
 #include <array>
-#include <iostream>
 
 // Based on: https://www.kalmanfilter.net/alphabeta.html#ex3
 
diff --git a/example/kalman_filter/kalman_filter-example_4.cpp b/example/kalman_filter/kalman_filter-example_4.cpp
index 9ae3a62a..d875b26c 100644
--- a/example/kalman_filter/kalman_filter-example_4.cpp
+++ b/example/kalman_filter/kalman_filter-example_4.cpp
@@ -26,8 +26,8 @@
 #include <units/isq/si/speed.h>
 #include <units/isq/si/time.h>
 #include <units/format.h>
+#include <units/generic/dimensionless.h>
 #include <array>
-#include <iostream>
 
 // Based on: https://www.kalmanfilter.net/alphabeta.html#ex4
 
diff --git a/example/kalman_filter/kalman_filter-example_5.cpp b/example/kalman_filter/kalman_filter-example_5.cpp
index cd99ddd6..de5385c0 100644
--- a/example/kalman_filter/kalman_filter-example_5.cpp
+++ b/example/kalman_filter/kalman_filter-example_5.cpp
@@ -25,7 +25,6 @@
 #include <units/format.h>
 #include <units/math.h>
 #include <array>
-#include <iostream>
 
 // Based on: https://www.kalmanfilter.net/kalman1d.html#ex5
 
diff --git a/example/kalman_filter/kalman_filter-example_6.cpp b/example/kalman_filter/kalman_filter-example_6.cpp
index 06c291d4..b9c590ab 100644
--- a/example/kalman_filter/kalman_filter-example_6.cpp
+++ b/example/kalman_filter/kalman_filter-example_6.cpp
@@ -25,8 +25,8 @@
 #include <units/format.h>
 #include <units/math.h>
 #include <units/quantity_point.h>
+#include <units/unit.h>
 #include <array>
-#include <iostream>
 
 // TODO Fix when Celsius is properly supported (#232)
 namespace units::isq::si {
diff --git a/example/kalman_filter/kalman_filter-example_7.cpp b/example/kalman_filter/kalman_filter-example_7.cpp
index 8911c020..0af1d939 100644
--- a/example/kalman_filter/kalman_filter-example_7.cpp
+++ b/example/kalman_filter/kalman_filter-example_7.cpp
@@ -25,8 +25,8 @@
 #include <units/format.h>
 #include <units/math.h>
 #include <units/quantity_point.h>
+#include <units/unit.h>
 #include <array>
-#include <iostream>
 
 // TODO Fix when Celsius is properly supported (#232)
 namespace units::isq::si {
diff --git a/example/kalman_filter/kalman_filter-example_8.cpp b/example/kalman_filter/kalman_filter-example_8.cpp
index 7d7100ae..09d3659a 100644
--- a/example/kalman_filter/kalman_filter-example_8.cpp
+++ b/example/kalman_filter/kalman_filter-example_8.cpp
@@ -25,8 +25,8 @@
 #include <units/format.h>
 #include <units/math.h>
 #include <units/quantity_point.h>
+#include <units/unit.h>
 #include <array>
-#include <iostream>
 
 // TODO Fix when Celsius is properly supported (#232)
 namespace units::isq::si {