\begin{thebibliography}{10}

\bibitem{draft-ietf-mmusic-sip}
M.~Handley, H.~Schulzrinne, E.~Schooler, and J.~Rosenberg, ``{SIP:} session
  initiation protocol,'' {Internet Draft}, Internet Engineering Task Force,
  Jan. 1999.
\newblock Work in progress.

\bibitem{h.323}
{International Telecommunication Union}, ``Visual telephone systems and
  equipment for local area networks which provide a non-guaranteed quality of
  service,'' Recommendation H.323, Telecommunication Standardization Sector of
  ITU, Geneva, Switzerland, May 1996.

\bibitem{xml}
T.~Bray, J.~Paoli, and C.~M. Sperberg-McQueen, ``Extensible markup language
  ({XML}) 1.0,'' {W3C} Recommendation 10-February-1998, World Wide Web
  Consortium ({W3C}), Feb. 1998.
\newblock {http://www.w3.org/TR/REC-xml}.

\bibitem{rfc2119}
S.~Bradner, ``Key words for use in {RFCs} to indicate requirement levels,'' BC
  2119, Internet Engineering Task Force, Mar. 1997.

\bibitem{html4}
D.~Raggett, A.~L. Hors, and I.~Jacobs, ``{HTML} 4.0 specification,'' {W3C}
  Recommendation revised on 24-Apr-1998, World Wide Web Consortium ({W3C}),
  Apr. 1998.
\newblock {http://www.w3.org/TR/REC-html40/}.

\bibitem{sgml}
{ISO (International Organization for Standardization)}, ``Information
  processing --- text and office systems --- standard generalized markup
  language ({SGML}),'' {ISO} Standard {ISO 8879:1986(E)}, International
  Organization for Standardization, Geneva, Oct. 1986.

\bibitem{rfc2244}
J.~Myers and C.~Newman, ``{ACAP} -- application configuration access
  protocol,'' Request for Comments (Proposed Standard) 2244, Internet
  Engineering Task Force, Dec. 1997.

\bibitem{rfc2445}
F.~Dawson and D.~Stenerson, ``Internet calendaring and scheduling core object
  specification (icalendar),'' Request for Comments (Proposed Standard) 2445,
  Internet Engineering Task Force, Nov. 1998.

\bibitem{xlink}
E.~Maler and S.~DeRose, ``{XML} linking language ({XLink}),'' Working Draft
  3-March-1998, World Wide Web Consortium ({W3C}), Mar. 1998.
\newblock {http://www.w3.org/TR/WD-xlink}.

\bibitem{Corm90:Introduction}
T.~H. Cormen, C.~E. Leiserson, and R.~L. Rivest, {\em Introduction to
  Algorithms}.
\newblock New York: McGraw-Hill, 1990.

\bibitem{draft-showalter-sieve}
T.~Showalter, ``Sieve: A mail filtering language,'' {Internet Draft}, Internet
  Engineering Task Force, Jan. 1999.
\newblock Work in progress.

\end{thebibliography}
