%% You should probably cite draft-ietf-sipping-reg-event instead of this I-D.
@techreport{rosenberg-sip-reg-00,
    number =    {draft-rosenberg-sip-reg-00},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-rosenberg-sip-reg/00/},
    author =    {Jonathan Rosenberg},
    title =     {{A Session Initiation Protocol (SIP) Event Package for Registrations}},
    pagetotal = 24,
    year =      2002,
    month =     may,
    day =       28,
    abstract =  {This document defines a Session Initiation Protocol (SIP) event package for registrations. Through its REGISTER method, SIP allows a user agent to create, modify, and delete registrations. Registrations can also be altered by administrators in order to enforce policy. These registrations therefore represent a piece of state in the network that can change dynamically. There are many cases where a user agent would like to be notified of changes in this state. This event package defines a mechanism by which those user agents can request and obtain such notifications},
}