diff --git a/doc.go b/doc.go
index e2cbbfe..5e1c074 100644
--- a/doc.go
+++ b/doc.go
@@ -21,6 +21,8 @@ XMPP components can typically be used to extends the features of an XMPP
 server, in a portable way, using component protocol over persistent TCP
 connections.
 
+Component protocol is defined in XEP-114 (https://xmpp.org/extensions/xep-0114.html).
+
 Compliance
 
 Fluux XMPP has been primarily tested with ejabberd (https://www.ejabberd.im)