%% You should probably cite draft-ietf-sipcore-proxy-feature instead of this I-D. @techreport{holmberg-sipcore-proxy-feature-04, number = {draft-holmberg-sipcore-proxy-feature-04}, type = {Internet-Draft}, institution = {Internet Engineering Task Force}, publisher = {Internet Engineering Task Force}, note = {Work in Progress}, url = {https://datatracker.ietf.org/doc/draft-holmberg-sipcore-proxy-feature/04/}, author = {Christer Holmberg and Ivo Sedlacek and Hadriel Kaplan}, title = {{Indication of features supported by proxy}}, pagetotal = 12, year = 2011, month = dec, day = 12, abstract = {This document defines a new SIP header field, Feature-Caps, that can be used by SIP entities to indicate support of features and capabilities, in cases where the Contact header field contains a URI that does not represent the SIP entity that wants to indicate support of its features and capabilities.}, }