%% You should probably cite draft-ietf-enum-pstn instead of this I-D.
@techreport{livingood-shockey-enum-npd-00,
    number =    {draft-livingood-shockey-enum-npd-00},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-livingood-shockey-enum-npd/00/},
    author =    {Jason Livingood and Richard D. Shockey},
    title =     {{IANA Registration for an Enumservice Containing Number Portability and PSTN Signaling Information}},
    pagetotal = 8,
    year =      2005,
    month =     jul,
    day =       8,
    abstract =  {This document registers the Enumservice “npd” and subtype “tel” using the URI scheme ‘tel:’ as per the IANA registration process defined in the ENUM specification, RFC 3761. This data is used to facilitate the routing of telephone calls in those countries where Number Portability exists.},
}