diff --git a/docs/act_start_chapter.sgml b/docs/act_start_chapter.sgml
index e458004832718b405518160f89339505307bd23f..d595c52cd90fea0912c59920db82274e6df90f4d 100644
--- a/docs/act_start_chapter.sgml
+++ b/docs/act_start_chapter.sgml
@@ -44,6 +44,13 @@ an easier to read format.  MSPcrunch much be run with the
       </LISTITEM>
     </ITEMIZEDLIST>
 
+    <PARA>
+       Anthony Underwood and Jonathan Green at the <ULINK URL="http://www.hpa.org.uk/">
+       Health Protection Agency</ULINK> have developed an online tool, <ULINK 
+       URL="http://193.129.245.227/pise/double_act.html">Double ACT</ULINK>, to generate
+       ACT comparison files.
+    </PARA>
+    
     <SECT2 ID="COMPARISON-BIG-BLAST">
       <TITLE><COMMAND>big_blast.pl</COMMAND></TITLE>
       <PARA>