%% You should probably cite rfc5527 instead of this I-D.
@techreport{ietf-enum-combined-09,
    number =    {draft-ietf-enum-combined-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-enum-combined/09/},
    author =    {Michael Haberler and Otmar Lendl and Richard Stastny},
    title =     {{Combined User and Infrastructure ENUM in the e164.arpa Tree}},
    pagetotal = 10,
    year =      2009,
    month =     mar,
    day =       5,
    abstract =  {This memo defines an interim solution for Infrastructure ENUM in order to allow a combined User and Infrastructure ENUM implementation in e164.arpa as a national choice. This interim solution will be deprecated after implementation of the long-term solution. This memo provides information for the Internet community.},
}