diff --git a/supplemental/Klingon.txt b/supplemental/Klingon.txt
index c5acb9b4..543fa112 100644
--- a/supplemental/Klingon.txt
+++ b/supplemental/Klingon.txt
@@ -1,4 +1,6 @@
 # Code Point ; Script ; General Category ; Name ; Okrand Transliteration
+#
+# Reference: http://www.evertype.com/standards/csur/klingon.html
 
 F8D0;Qaak;Lo;KLINGON LETTER A;a
 F8D1;Qaak;Lo;KLINGON LETTER B;a