diff --git a/reference/gmp/functions/gmp-sign.xml b/reference/gmp/functions/gmp-sign.xml
index 5b1a044468..18128ac5cb 100644
--- a/reference/gmp/functions/gmp-sign.xml
+++ b/reference/gmp/functions/gmp-sign.xml
@@ -71,6 +71,16 @@ echo gmp_sign("0") . "\n";
   </para>
  </refsect1>
 
+ <refsect1 role="seealso">
+  &reftitle.seealso;
+  <para>
+   <simplelist>
+    <member><function>gmp_abs</function></member>
+    <member><function>abs</function></member>
+   </simplelist>
+  </para>
+ </refsect1>
+
 </refentry>
 
 <!-- Keep this comment at the end of the file
diff --git a/reference/math/functions/abs.xml b/reference/math/functions/abs.xml
index e94a415f22..2b702ab77f 100644
--- a/reference/math/functions/abs.xml
+++ b/reference/math/functions/abs.xml
@@ -57,6 +57,17 @@ $abs3 = abs(-5);  // $abs3 = 5; (integer)
    </example>
   </para>
  </refsect1>
+
+ <refsect1 role="seealso">
+  &reftitle.seealso;
+  <para>
+   <simplelist>
+    <member><function>gmp_abs</function></member>
+    <member><function>gmp_sign</function></member>
+   </simplelist>
+  </para>
+ </refsect1>
+
 </refentry>
 
 <!-- Keep this comment at the end of the file