%% You should probably cite rfc4769 instead of this I-D.
@techreport{ietf-enum-pstn-05,
    number =    {draft-ietf-enum-pstn-05},
    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-enum-pstn/05/},
    author =    {Richard Shockey and Jason Livingood},
    title =     {{IANA Registration for an Enumservice Containing Public Switched Telephone Network (PSTN) Signaling Information}},
    pagetotal = 13,
    year =      2006,
    month =     aug,
    day =       7,
    abstract =  {This document registers the Enumservice type "pstn" and subtype "tel" using the URI scheme 'tel', as well as the subtype "sip" using the URI scheme 'sip' as per the IANA registration process defined in the ENUM specification, RFC 3761. This Enumservice is used to facilitate the routing of telephone calls in those countries where number portability exists. {[}STANDARDS-TRACK{]}},
}