diff --git a/doc/19-language-reference.md b/doc/19-language-reference.md
index c0d843b82..c92a18724 100644
--- a/doc/19-language-reference.md
+++ b/doc/19-language-reference.md
@@ -85,6 +85,7 @@ Character                 | Escape sequence
 --------------------------|------------------------------------
 "                         | \\"
 \\                        | \\\\
+$                         | $$
 <TAB>               | \\t
 <CARRIAGE-RETURN>   | \\r
 <LINE-FEED>         | \\n