Added pointer on POP3 variations.

Doc/lib/libpoplib.tex

@@ -127,6 +127,10 @@ otherwise result is list \code{(\var{response}, ['mesgnum uid', ...],
 
 \begin{seealso}
   \seemodule{imap}{The standard Python IMAP module.}
+  \seetitle{http://www.tuxedo.org/~esr/fetchail/fetchmail-FAQ.html}{
+	The FAQ for the fetchmail POP/IMAP client collects information
+	on POP3 server variations and RFC noncompliance that may be
+	useful if you need to write an application based on poplib.} 
 \end{seealso}
 
 \subsection{POP3 Example \label{pop3-example}}