CONTRIBUTORS

--- a/CONTRIBUTORS	Tue Jun 05 15:17:02 2007 +0200
+++ b/CONTRIBUTORS	Tue Jun 05 16:26:04 2007 +0200
@@ -1,6 +1,9 @@
 
-Contributions to Isabelle
--------------------------
+Contributions to Isabelle 2007
+------------------------------
+
+* June 2007: Amine Chaieb, TUM
+  Semiring normalization and Groebner Bases
 
 * 2006/2007: Florian Haftmann, TUM
   Pure: generic code generator framework.