%% You should probably cite rfc7044 instead of this I-D. @techreport{ietf-sipcore-rfc4244bis-11, number = {draft-ietf-sipcore-rfc4244bis-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-ietf-sipcore-rfc4244bis/11/}, author = {Mary Barnes and Francois Audet and Shida Schubert and Hans Erik van Elburg and Christer Holmberg}, title = {{An Extension to the Session Initiation Protocol (SIP) for Request History Information}}, pagetotal = 36, year = 2013, month = jan, day = 11, 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 SIP request arrives at a specific application or user. This document defines an optional SIP header field, History-Info, for capturing the history information in requests. The document also defines SIP header field parameters for the History-Info and Contact header fields to tag the method by which the target of a request is determined. In addition, this specification defines a value for the Privacy header field that directs the anonymization of values in the History-Info header field. This document obsoletes RFC 4244.}, }