Another contributor.
diff --git a/Misc/ACKS b/Misc/ACKS
index 4aa9026..07aef56 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -414,6 +414,7 @@
 Greg Stein
 Dan Stromberg
 Nathan Sullivan
+Mark Summerfield
 Kalle Svensson
 Hajime Saitou
 RajGopal Srinivasan