%% You should probably cite rfc7621 instead of this I-D.
@techreport{ietf-sipcore-6665-clarification-00,
    number =    {draft-ietf-sipcore-6665-clarification-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-ietf-sipcore-6665-clarification/00/},
    author =    {Adam Roach},
    title =     {{A Clarification on the Use of Globally Routable User Agent URIs (GRUUs) in the SIP Event Notification Framework}},
    pagetotal = 4,
    year =      2015,
    month =     feb,
    day =       27,
    abstract =  {Experience since the publication of the most recent SIP Events framework (in July 2012) has shown that there is room for interpretation around the use of Globally Routable User Agent URIs in that specification. This document clarifies the intended behavior. This document updates RFC 6665.},
}