diff --git a/servers/slapd/phonetic.c b/servers/slapd/phonetic.c
index 80522af3e7..bfd2011be1 100644
--- a/servers/slapd/phonetic.c
+++ b/servers/slapd/phonetic.c
@@ -163,6 +163,10 @@ phonetic( char *s )
 
 #elif defined(SLAPD_METAPHONE)
 
+/*
+ * Metaphone was originally developed by Lawrence Philips and
+ * published in the "Computer Language" magazine in 1990.
+ */
 /*
  * Metaphone copied from C Gazette, June/July 1991, pp 56-57,
  * author Gary A. Parker, with changes by Bernard Tiffany of the