[1] RFC 3340 - The Application Exchange Core ( 版) https://tools.ietf.org/html/rfc3340
[2] RFC 3341 - The Application Exchange (APEX) Access Service ( 版) https://tools.ietf.org/html/rfc3341
[3] RFC 3342 - The Application Exchange (APEX) Option Party Pack, Part Deux! ( 版) https://tools.ietf.org/html/rfc3342
[4] RFC 3343 - The Application Exchange (APEX) Presence Service ( 版) https://tools.ietf.org/html/rfc3343