%% You should probably cite rfc4904 instead of this I-D.
@techreport{ietf-iptel-trunk-group-10,
    number =    {draft-ietf-iptel-trunk-group-10},
    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-iptel-trunk-group/10/},
    author =    {Cullen Fluffy Jennings and Vijay K. Gurbani},
    title =     {{Representing Trunk Groups in tel/sip Uniform Resource Identifiers (URIs)}},
    pagetotal = 19,
    year =      2007,
    month =     jan,
    day =       22,
    abstract =  {This document describes a standardized mechanism to convey trunk group parameters in sip and tel Uniform Resource Identifiers (URIs). An extension to the tel URI is defined for this purpose. {[}STANDARDS-TRACK{]}},
}