%% You should probably cite rfc4715 instead of this I-D.
@techreport{munakata-iptel-isub-type-04,
    number =    {draft-munakata-iptel-isub-type-04},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-munakata-iptel-isub-type/04/},
    author =    {Shida Schubert and Takumi Ohba and Mayumi Munakata},
    title =     {{The Integrated Services Digital Network (ISDN) Subaddress Encoding Type for tel URI}},
    pagetotal = 14,
    year =      2006,
    month =     jul,
    day =       25,
    abstract =  {Without a tel URI parameter to carry an encoding type of Integrated Services Digital Network (ISDN) subaddress, interworking between ISDN User Part (ISUP) network and a Session Initiation Protocol (SIP) network is impossible in some cases. To solve this problem, this document specifies a new optional tel URI parameter to carry the encoding type of ISDN subaddress. This memo provides information for the Internet community.},
}