CONTRIBUTORS

--- a/CONTRIBUTORS	Mon Oct 04 13:53:41 2021 +0200
+++ b/CONTRIBUTORS	Mon Oct 04 14:02:11 2021 +0200
@@ -6,6 +6,9 @@
 Contributions to Isabelle2021-1
 -------------------------------
 
+* July .. September 2021: Makarius Wenzel
+  Significantly improved Isabelle/Haskell library.
+
 * July 2021: Florian Haftmann
   Further consolidation of bit operations and word types.