diff --git a/doc/ack.texi b/doc/ack.texi
index d7f69fa10..0aa2f6b0a 100644
--- a/doc/ack.texi
+++ b/doc/ack.texi
@@ -66,6 +66,7 @@ Bugfixes, documentation, encouragement, and code has been contributed by:
 @item Petr Holub
 @item Phil Fisher
 @item Rafal Malinowski
+@item Rainer Toebbicke
 @item Richard Nyberg
 @item Stefan Metzmacher
 @item Zeqing Xia