--- a/semantics/checker.pl	Thu Feb 21 15:39:01 2013 +0000
+++ b/semantics/checker.pl	Thu Feb 21 15:39:47 2013 +0000
@@ -1,5 +1,8 @@
 % James Cheney, February 6, 2013
 % Some  Prolog code for PROV-CONSTRAINTS
+% A full version of this checker can be found at 
+% https://github.com/jamescheney/prov-constraints 
+
 
 :- consult(prov_xml).