diff --git a/doc/vic20.sgml b/doc/vic20.sgml
index e292e0a1a..4fcd0079c 100644
--- a/doc/vic20.sgml
+++ b/doc/vic20.sgml
@@ -107,6 +107,7 @@ declaration and usage.
 <item>cbm_save
 <item>cbm_write
 <item>get_tv
+<item>waitvsync
 </itemize>