Fix some markup errors.
diff --git a/Doc/lib/libsocket.tex b/Doc/lib/libsocket.tex
index 2468aec..e540f8f 100644
--- a/Doc/lib/libsocket.tex
+++ b/Doc/lib/libsocket.tex
@@ -19,8 +19,8 @@
of information on the details of socket semantics. For \UNIX, refer
to the manual pages; for Windows, see the WinSock (or Winsock 2)
specification.
-For IPv6-ready APIs, readers may want to refer to RFC2553 titled
-\cite{Basic Socket Interface Extensions for IPv6}.
+For IPv6-ready APIs, readers may want to refer to \rfc{2553} titled
+\citetitle{Basic Socket Interface Extensions for IPv6}.
The Python interface is a straightforward transliteration of the
\UNIX{} system call and library interface for sockets to Python's