diff --git a/functions/math.xml b/functions/math.xml
index 47c4a246ce..a366474fad 100644
--- a/functions/math.xml
+++ b/functions/math.xml
@@ -1,7 +1,7 @@
  <reference id="ref.math">
   <title>Mathematical Functions</title>
   <titleabbrev>Math.</titleabbrev>
-
+  
   <partintro>
    <sect1>
     <title>Introduction</title>
@@ -556,6 +556,28 @@ $binary = base_convert ($hexadecimal, 16, 2);
    </refsect1>
   </refentry>
 
+  <refentry id="function.lcg-value">
+   <refnamediv>
+    <refname>lcg_value</refname>
+    <refpurpose>Combined linear congruential generator</refpurpose>
+   </refnamediv>
+   <refsect1>
+    <title>Description</title>
+    <funcsynopsis>
+     <funcprototype>
+      <funcdef>double <function>lcg_value</function></funcdef>
+      <void/>
+     </funcprototype>
+    </funcsynopsis>
+    <para>
+     <function>lcg_value</function> returns a pseudo random number in
+     the range of (0, 1).  The function combines two CGs with periods
+     of 2^31 - 85 and 2^31 - 249. The period of this function is equal
+     to the product of both primes.
+    </para>
+   </refsect1>
+  </refentry>
+
   <refentry id="function.log">
    <refnamediv>
     <refname>log</refname>