diff --git a/doc/zmq_setsockopt.txt b/doc/zmq_setsockopt.txt
index e4f51368..8b5617f4 100644
--- a/doc/zmq_setsockopt.txt
+++ b/doc/zmq_setsockopt.txt
@@ -39,6 +39,10 @@ blocking or dropping sent messages. Refer to the individual socket descriptions
 in linkzmq:zmq_socket[3] for details on the exact action taken for each socket
 type.
 
+NOTE: 0MQ does not guarantee that the socket will accept as many as ZMQ_SNDHWM
+messages, and the actual limit may be as much as 60-70% lower depending on the
+flow of messages on the socket.
+
 [horizontal]
 Option value type:: int
 Option value unit:: messages
diff --git a/doc/zmq_tcp.txt b/doc/zmq_tcp.txt
index a87aaa0c..1602ede3 100644
--- a/doc/zmq_tcp.txt
+++ b/doc/zmq_tcp.txt
@@ -58,6 +58,8 @@ A 'peer address' may be specified by either of the following:
 * The DNS name of the peer.
 * The IPv4 or IPv6 address of the peer, in its numeric representation.
 
+Note: A description of the ZeroMQ Message Transport Protocol (ZMTP) which is 
+used by the TCP transport can be found at <http://rfc.zeromq.org/spec:15>
 
 EXAMPLES
 --------