diff --git a/lib/pop3.c b/lib/pop3.c
index 08c0de57ebe21d086f1d76e3e4f9ad87bede4368..df199b00cbf1d677f2d829277a23236693079981 100644
--- a/lib/pop3.c
+++ b/lib/pop3.c
@@ -21,6 +21,7 @@
  * RFC1734 POP3 Authentication
  * RFC1939 POP3 protocol
  * RFC2195 CRAM-MD5 authentication
+ * RFC2222 Simple Authentication and Security Layer (SASL)
  * RFC2384 POP URL Scheme
  * RFC2449 POP3 Extension Mechanism
  * RFC2595 Using TLS with IMAP, POP3 and ACAP