@misc{rfc5009,
    series =    {Request for Comments},
    number =    5009,
    howpublished =  {RFC 5009},
    publisher = {RFC Editor},
    doi =       {10.17487/RFC5009},
    url =       {https://www.rfc-editor.org/info/rfc5009},
    author =    {Richard Ejzak},
    title =     {{Private Header (P-Header) Extension to the Session Initiation Protocol (SIP) for Authorization of Early Media}},
    pagetotal = 15,
    year =      2007,
    month =     sep,
    abstract =  {This document describes a private Session Initiation Protocol (SIP) header field (P-header) to be used by the European Telecommunications Standards Institute (ETSI) Telecommunications and Internet-converged Services and Protocols for Advanced Networks (TISPAN) for the purpose of authorizing early media flows in Third Generation Partnership Project (3GPP) IP Multimedia Subsystems (IMS). This header field is useful in any SIP network that is interconnected with other SIP networks and needs to control the flow of media in the early dialog state. This memo provides information for the Internet community.},
}