add RFC cite

diff --git a/doc/message.rst b/doc/message.rst
index 48b7387f31fc5578ed7ec245017afdae1676d22e..c953f61e8b65bc496101082c4206f080958b28d8 100644 (file)
--- a/doc/message.rst
+++ b/doc/message.rst
@@ -4,7 +4,9 @@
 DNS Messages
 ============
 
-Objects of the dns.message.Message class represent a single DNS message.
+Objects of the dns.message.Message class represent a single DNS message,
+as defined by `RFC 1035 <https://tools.ietf.org/html/rfc1035>`_ and its
+many updates and extensions.
 
 The module provides tools for constructing and manipulating messages.
 TSIG signatures and EDNS are also supported.  Messages can be dumped to