CONTRIBUTORS

--- a/CONTRIBUTORS	Mon Dec 21 13:03:23 2020 +0100
+++ b/CONTRIBUTORS	Mon Dec 21 13:58:11 2020 +0100
@@ -5,6 +5,10 @@
 
 Contributions to this Isabelle version
 --------------------------------------
+
+* December 2020: Martin Desharnais
+  Zipperposition 2.0 as external prover for Sledgehammer (experimental).
+
 * December 2020 Walter Guttmann
   Extension of session HOL/Hoare with total correctness proof system