diff --git a/doc/ref.xml b/doc/ref.xml
index 941894d..ca92c20 100644
--- a/doc/ref.xml
+++ b/doc/ref.xml
@@ -370,6 +370,8 @@ file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
         </method>
       </struct-specialization>
 
+      <free-function-group name="Support functions (Boost extension).">
+
       <!--
         boost::hash_combine
         -->
@@ -464,6 +466,10 @@ for(; first != last; ++first)
         </para></throws>
       </overloaded-function>
 
+      </free-function-group>
+
+      <free-function-group name="Overloadable hash implementation (Boost extension).">
+
       <!--
         boost::hash_value - integers
         -->
@@ -694,6 +700,7 @@ return seed;</programlisting></entry>
           </informaltable>
         </returns>
       </overloaded-function>
+      </free-function-group>
     </namespace>
   </header>
 </library-reference>
diff --git a/doc/thanks.qbk b/doc/thanks.qbk
index 6aabb54..27bffc1 100644
--- a/doc/thanks.qbk
+++ b/doc/thanks.qbk
@@ -5,16 +5,15 @@
 
 [section:acknowledgements Acknowledgements]
 
-This library is based on the design by Peter Dimov's original design.
-
-During the initial development Joaquín M López Muñoz made many useful
-suggestions, contributed fixes.
+This library is based on the design by Peter Dimov. During the initial
+development
+Joaquín M López Muñoz made many useful suggestions and contributed fixes.
 
 The formal review was managed by Thorsten Ottosen, and the library reviewed by:
 David Abrahams, Alberto Barbati, Topher Cooper, Caleb Epstein, Dave Harris,
-Chris Jefferson, Bronek Kozicki, John Maddock, Tobias Swinger, Jaap Suter, Rob
-Stewart and Pavel Vozenilek. Since then, there have been further contributions
-from Daniel Krügler, Alexander Nasonov, 沈慧峰 and John Maddock.
+Chris Jefferson, Bronek Kozicki, John Maddock, Tobias Swinger, Jaap Suter,
+Rob Stewart and Pavel Vozenilek. Since then, further constructive criticism has
+been made by Daniel Krügler, Alexander Nasonov and 沈慧峰.
 
 The implementation of the hash function for pointers is based on suggestions
 made by Alberto Barbati and Dave Harris. Dave Harris also suggested an
diff --git a/doc/tutorial.qbk b/doc/tutorial.qbk
index e8ab61a..e30a181 100644
--- a/doc/tutorial.qbk
+++ b/doc/tutorial.qbk
@@ -119,7 +119,7 @@ When writing a hash function, first look at how the equality function works.
 Objects that are equal must generate the same hash value.
 When objects are not equal they should generate different hash values.
 In this object equality was based just on the id so the hash function
-only hash the id. If it was based on the objects name and author
+only hashes the id. If it was based on the object's name and author
 then the hash function should take them into account
 (how to do this is discussed in the next section).
 ]