%% You should probably cite rfc3966 instead of this I-D.
@techreport{ietf-iptel-rfc2806bis-09,
    number =    {draft-ietf-iptel-rfc2806bis-09},
    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-rfc2806bis/09/},
    author =    {Henning Schulzrinne},
    title =     {{The tel URI for Telephone Numbers}},
    pagetotal = 17,
    year =      2004,
    month =     jun,
    day =       29,
    abstract =  {This document specifies the URI (Uniform Resource Identifier) scheme "tel". The "tel" URI describes resources identified by telephone numbers. This document obsoletes RFC 2806. {[}STANDARDS-TRACK{]}},
}