diff --git a/docs/docs/ml.xml b/docs/docs/ml.xml
index 152602876..a90e14972 100644
--- a/docs/docs/ml.xml
+++ b/docs/docs/ml.xml
@@ -137,6 +137,7 @@ Davis E. King. <a href="http://www.jmlr.org/papers/volume10/king09a/king09a.pdf"
             <name>manifold_regularization_tools</name>
             <sub>
                <item>sample_pair</item>
+               <item>ordered_sample_pair</item>
                <item>find_percent_shortest_edges_randomly</item>
                <item>find_k_nearest_neighbors</item>
                <item>find_approximate_k_nearest_neighbors</item>
@@ -336,7 +337,7 @@ Davis E. King. <a href="http://www.jmlr.org/papers/volume10/king09a/king09a.pdf"
          <spec_file link="true">dlib/manifold_regularization/graph_creation_abstract.h</spec_file>
          <description>
             This is a simple function for removing edges with a small distance value from
-            a vector of <a href="#sample_pair">sample_pairs</a>.
+            a vector of <a href="#sample_pair">sample_pair</a> or <a href="#ordered_sample_pair">ordered_sample_pair</a> objects.
          </description>
 
       </component>
@@ -349,7 +350,8 @@ Davis E. King. <a href="http://www.jmlr.org/papers/volume10/king09a/king09a.pdf"
          <spec_file link="true">dlib/manifold_regularization/graph_creation_abstract.h</spec_file>
          <description>
             This is a simple function for removing duplicate edges (i.e. edges that compare equal 
-            according to ==) from a vector of <a href="#sample_pair">sample_pairs</a>.
+            according to ==) from 
+            a vector of <a href="#sample_pair">sample_pair</a> or <a href="#ordered_sample_pair">ordered_sample_pair</a> objects.
          </description>
       </component>
 
@@ -361,7 +363,7 @@ Davis E. King. <a href="http://www.jmlr.org/papers/volume10/king09a/king09a.pdf"
          <spec_file link="true">dlib/manifold_regularization/graph_creation_abstract.h</spec_file>
          <description>
             This is a simple function for removing edges with a small distance value from
-            a vector of <a href="#sample_pair">sample_pairs</a>.
+            a vector of <a href="#sample_pair">sample_pair</a> or <a href="#ordered_sample_pair">ordered_sample_pair</a> objects.
          </description>
 
       </component>
@@ -374,7 +376,7 @@ Davis E. King. <a href="http://www.jmlr.org/papers/volume10/king09a/king09a.pdf"
          <spec_file link="true">dlib/manifold_regularization/graph_creation_abstract.h</spec_file>
          <description>
             This is a simple function for removing edges with a large distance value from
-            a vector of <a href="#sample_pair">sample_pairs</a>.
+            a vector of <a href="#sample_pair">sample_pair</a> or <a href="#ordered_sample_pair">ordered_sample_pair</a> objects.
          </description>
 
       </component>
@@ -387,7 +389,7 @@ Davis E. King. <a href="http://www.jmlr.org/papers/volume10/king09a/king09a.pdf"
          <spec_file link="true">dlib/manifold_regularization/graph_creation_abstract.h</spec_file>
          <description>
             This is a simple function for removing edges with a large distance value from
-            a vector of <a href="#sample_pair">sample_pairs</a>.
+            a vector of <a href="#sample_pair">sample_pair</a> or <a href="#ordered_sample_pair">ordered_sample_pair</a> objects.
          </description>
 
       </component>
@@ -425,14 +427,14 @@ Davis E. King. <a href="http://www.jmlr.org/papers/volume10/king09a/king09a.pdf"
 
    <!-- ************************************************************************* -->
 
-      
       <component>
          <name>sample_pair</name>
          <file>dlib/manifold_regularization.h</file>
          <spec_file link="true">dlib/manifold_regularization/sample_pair_abstract.h</spec_file>
          <description>
             This object is intended to represent an edge in an undirected graph 
-                which has data samples at its vertices.  
+                which has data samples at its vertices.  Therefore, it is the undirected version
+                of <a href="#ordered_sample_pair">ordered_sample_pair</a>.
          </description>
 
          <examples>
@@ -441,6 +443,19 @@ Davis E. King. <a href="http://www.jmlr.org/papers/volume10/king09a/king09a.pdf"
                                  
       </component>
 
+   <!-- ************************************************************************* -->
+
+      <component>
+         <name>ordered_sample_pair</name>
+         <file>dlib/manifold_regularization.h</file>
+         <spec_file link="true">dlib/manifold_regularization/ordered_sample_pair_abstract.h</spec_file>
+         <description>
+            This object is intended to represent an edge in a directed graph 
+                which has data samples at its vertices.  Therefore, it is the directed version
+                of <a href="#sample_pair">sample_pair</a>.
+         </description>
+      </component>
+
    <!-- ************************************************************************* -->
 
       
diff --git a/docs/docs/term_index.xml b/docs/docs/term_index.xml
index e856ce1e5..511e6fb02 100644
--- a/docs/docs/term_index.xml
+++ b/docs/docs/term_index.xml
@@ -219,8 +219,10 @@
          <term file="ml.html" name="empirical_kernel_map"/>
 
          <term file="ml.html" name="sample_pair"/>
+         <term file="ml.html" name="ordered_sample_pair"/>
          <term file="dlib/manifold_regularization/sample_pair_abstract.h.html" name="order_by_index"/>
          <term file="dlib/manifold_regularization/sample_pair_abstract.h.html" name="order_by_distance"/>
+         <term file="dlib/manifold_regularization/sample_pair_abstract.h.html" name="order_by_distance_and_index"/>
          <term file="ml.html" name="find_percent_shortest_edges_randomly"/>
          <term file="ml.html" name="find_k_nearest_neighbors"/>
          <term file="ml.html" name="remove_short_edges"/>