%% You should probably cite draft-jesske-sipcore-sip-tree-cap-indicators instead of this I-D.
@techreport{allen-sipcore-sip-tree-cap-indicators-02,
    number =    {draft-allen-sipcore-sip-tree-cap-indicators-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-allen-sipcore-sip-tree-cap-indicators/02/},
    author =    {Andrew Allen and Roland Jesske},
    title =     {{Internet Assigned Numbers Authority (IANA) Registration of the Session Initiation Protocol (SIP) Feature-Capability indicators}},
    pagetotal = 16,
    year =      2018,
    month =     jan,
    day =       18,
    abstract =  {This document registers with IANA SIP Feature-Capability indicators in the "SIP Feature-Capability Indicator Registration Tree" of the IANA "Proxy-Feature Feature-Capability Indicator Trees" registry for use with the SIP Feature-Caps header field and defines their usage and interpretation.},
}