• [2] RFC 3959 - The Early Session Disposition Type for the Session Initiation Protocol (SIP) (2014-09-21 08:16:00 +09:00 版) http://tools.ietf.org/html/rfc3959
• [3] RFC Errata Report (2014-11-03 03:57:14 +09:00 版) http://www.rfc-editor.org/errata_search.php?rfc=3959
• [1] RFC 5621 - Message Body Handling in the Session Initiation Protocol (SIP) (2014-09-14 07:55:49 +09:00 版) http://tools.ietf.org/html/rfc5621#section-6.2