%% You should probably cite rfc3840 instead of this I-D. @techreport{ietf-sip-callee-caps-03, number = {draft-ietf-sip-callee-caps-03}, type = {Internet-Draft}, institution = {Internet Engineering Task Force}, publisher = {Internet Engineering Task Force}, note = {Work in Progress}, url = {https://datatracker.ietf.org/doc/draft-ietf-sip-callee-caps/03/}, author = {Henning Schulzrinne and Jonathan Rosenberg and Paul Kyzivat}, title = {{Indicating User Agent Capabilities in the Session Initiation Protocol (SIP)}}, pagetotal = 36, year = 2004, month = jan, day = 6, abstract = {This specification defines mechanisms by which a Session Initiation Protocol (SIP) user agent can convey its capabilities and characteristics to other user agents and to the registrar for its domain. This information is conveyed as parameters of the Contact header field. {[}STANDARDS-TRACK{]}}, }