diff --git a/index.html b/index.html
index d2101447..c0b51e53 100644
--- a/index.html
+++ b/index.html
@@ -3083,6 +3083,12 @@ https://...</pre>
     <li>
         <a href="http://ifwiki.org/index.php/Hugor">Hugor</a>
     </li>
+    <li>
+        <a href="http://www.qtrac.eu/diffpdf.html">DiffPDF</a>
+    </li>
+    <li>
+        <a href="http://pdfgrep.sourceforge.net/">Pdfgrep</a>
+    </li>
     </ul>
 </div>