--- a/index.html	Thu Mar 15 15:50:18 2012 +0000
+++ b/index.html	Thu Mar 15 15:55:30 2012 +0000
@@ -193,7 +193,7 @@
 fib and even/odd, we implemented a large part of regular language theory in Isabelle/HOL.
 This <A HREF="http://afp.sourceforge.net/devel-entries/Myhill-Nerode.shtml">implementation</A> 
 gives rise to much more interesting examples, as shown 
-<A HREF="http://www.cs.cmu.edu/~rwh/papers/regexp/jfp.ps">here</A> and 
+<A HREF="http://www.cs.cmu.edu/~rwh/papers/regexp/jfp.pdf">here</A> and 
 <A HREF="http://ropas.snu.ac.kr/~kwang/paper/06-jfp-yi.pdf">here</A>. It turns out that
 formalisations of automata theory are a huge 
 <A HREF="https://lists.cam.ac.uk/pipermail/cl-isabelle-users/2005-September/msg00012.html">pain</A>