\end{classdesc}
+\begin{seealso}
+ \seetitle[http://www.qmail.org/man/man5/mbox.html]{mbox -
+ file containing mail messages}{Description of the
+ traditional ``mbox'' mailbox format.}
+ \seetitle[http://www.qmail.org/man/man5/maildir.html]{maildir -
+ directory for incoming mail messages}{Description of the
+ ``maildir'' mailbox format.}
+ \seetitle[http://home.netscape.com/eng/mozilla/2.0/relnotes/demo/content-length.html]{Configuring
+ Netscape Mail on \UNIX: Why the Content-Length Format is
+ Bad}{A description of problems with relying on the
+ Content-Length header for messages stored in mailbox
+ files.}
+\end{seealso}
+
+
\subsection{Mailbox Objects \label{mailbox-objects}}
All implementations of Mailbox objects are iterator objects, and so