%% You should probably cite rfc7315 instead of this I-D. @techreport{drage-sipping-rfc3455bis-11, number = {draft-drage-sipping-rfc3455bis-11}, type = {Internet-Draft}, institution = {Internet Engineering Task Force}, publisher = {Internet Engineering Task Force}, note = {Work in Progress}, url = {https://datatracker.ietf.org/doc/draft-drage-sipping-rfc3455bis/11/}, author = {Roland Jesske and Keith Drage and Christer Holmberg}, title = {{Private Header (P-Header) Extensions to the Session Initiation Protocol (SIP) for the 3rd-Generation Partnership Project (3GPP)}}, pagetotal = 47, year = 2014, month = jan, day = 7, abstract = {This document describes a set of private Session Initiation Protocol (SIP) header fields (P-headers) used by the 3rd-Generation Partnership Project (3GPP), along with their applicability, which is limited to particular environments. The P-header fields are for a variety of purposes within the networks that the partners use, including charging and information about the networks a call traverses.}, }