%% You should probably cite draft-ietf-sip-refer-feature-param instead of this I-D.
@techreport{olson-sipping-refer-extensions-02,
    number =    {draft-olson-sipping-refer-extensions-02},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-olson-sipping-refer-extensions/02/},
    author =    {Sean Olson},
    title =     {{REFER extensions}},
    pagetotal = 12,
    year =      2004,
    month =     jul,
    day =       21,
    abstract =  {The REFER extensions presented in this draft are usage of Feature parameters with REFER and the ability to suppress an implicit subscription with REFER. The extensions have been discussed in SIPPING WG and are targeted to become SIP WG items.},
}