%% You should probably cite rfc4244 instead of this I-D. @techreport{ietf-sip-history-info-06, number = {draft-ietf-sip-history-info-06}, 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-history-info/06/}, author = {Mary Barnes}, title = {{An Extension to the Session Initiation Protocol (SIP) for Request History Information}}, pagetotal = 44, year = 2005, month = jan, day = 18, abstract = {This document defines a standard mechanism for capturing the history information associated with a Session Initiation Protocol (SIP) request. This capability enables many enhanced services by providing the information as to how and why a call arrives at a specific application or user. This document defines a new optional SIP header, History-Info, for capturing the history information in requests. {[}STANDARDS-TRACK{]}}, }