diff --git a/xep.ent b/xep.ent
index 365e2872..cb25eefe 100644
--- a/xep.ent
+++ b/xep.ent
@@ -382,6 +382,7 @@ THE SOFTWARE.
 <!ENTITY rfc0793 "<span class='ref'><link url='http://tools.ietf.org/html/rfc0793'>RFC 793</link></span> <note>RFC 793: Transmission Control Protocol &lt;<link url='http://tools.ietf.org/html/rfc0793'>http://tools.ietf.org/html/rfc0793</link>&gt;.</note>" >
 <!ENTITY rfc0822 "<span class='ref'><link url='http://tools.ietf.org/html/rfc0822'>RFC 822</link></span> <note>RFC 822: Standard for the Format of ARPA Internet Text Messages &lt;<link url='http://tools.ietf.org/html/rfc0822'>http://tools.ietf.org/html/rfc0822</link>&gt;.</note>" >
 <!ENTITY rfc0862 "<span class='ref'><link url='http://tools.ietf.org/html/rfc0862'>RFC 862</link></span> <note>RFC 862: Echo Protocol &lt;<link url='http://tools.ietf.org/html/rfc0862'>http://tools.ietf.org/html/rfc0862</link>&gt;.</note>" >
+<!ENTITY rfc0918 "<span class='ref'><link url='http://tools.ietf.org/html/rfc0918'>RFC 918</link></span> <note>RFC 918: Post Office Protocol &lt;<link url='http://tools.ietf.org/html/rfc0918'>http://tools.ietf.org/html/rfc0918</link>&gt;.</note>" >
 <!ENTITY rfc0958 "<span class='ref'><link url='http://tools.ietf.org/html/rfc0958'>RFC 958</link></span> <note>RFC 958: Network Time Protocol (NTP) &lt;<link url='http://tools.ietf.org/html/rfc0958'>http://tools.ietf.org/html/rfc0958</link>&gt;.</note>" >
 <!ENTITY rfc0959 "<span class='ref'><link url='http://tools.ietf.org/html/rfc0959'>RFC 959</link></span> <note>RFC 959: File Transfer Protocol &lt;<link url='http://tools.ietf.org/html/rfc0959'>http://tools.ietf.org/html/rfc0959</link>&gt;.</note>" >
 <!ENTITY rfc1034 "<span class='ref'><link url='http://tools.ietf.org/html/rfc1034'>RFC 1034</link></span> <note>RFC 1034: Domain Names - Concepts and Facilities &lt;<link url='http://tools.ietf.org/html/rfc1034'>http://tools.ietf.org/html/rfc1034</link>&gt;.</note>" >