References
[1] “Caller Preferences for the Session Initiation Protocol (SIP)” by J.
Rosenberg, H. Schulzrinne, and P. Kizivat. RFC 3841, August 2004.
[2] “Indicating User Agent Capabilities in the Session Initiation Protocol (SIP)”
by J. Rosenberg, H. Schulzrinne, and P. Kizivat. RFC 3840, August 2004.
[3] “Guidelines for Usage of the Session Initiation Protocol (SIP) Caller Prefer-
ences Extension” by J. Rosenberg, and P. Kizivat. Internet Draft, October
2005.
[4] “CPL: A Language for User Control of Internet Telephony Services” J.
Lennox and H. Schulzrinne. IETF Internet Draft, work in progress, May
2001.158 Chapter 8