%% You should probably cite rfc5875 instead of this I-D.
@techreport{ietf-sip-xcapevent-08,
    number =    {draft-ietf-sip-xcapevent-08},
    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-xcapevent/08/},
    author =    {Jari Urpalainen and Dean Willis},
    title =     {{An Extensible Markup Language (XML) Configuration Access Protocol (XCAP) Diff Event Package}},
    pagetotal = 27,
    year =      2009,
    month =     jul,
    day =       9,
    abstract =  {This document describes an "xcap-diff" SIP (Session Initiation Protocol) event package for the SIP Event Notification Framework, which clients can use to receive notifications of changes to Extensible Markup Language (XML) Configuration Access Protocol (XCAP) resources. The initial synchronization information exchange and document updates are based on the XCAP Diff format. {[}STANDARDS TRACK{]}},
}