%% You should probably cite rfc1549 instead of this I-D.
@techreport{ietf-pppext-hdlc-framing-02,
    number =    {draft-ietf-pppext-hdlc-framing-02},
    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-pppext-hdlc-framing/02/},
    author =    {William A. Simpson},
    title =     {{PPP in HDLC Framing}},
    pagetotal = 18,
    year =      1993,
    month =     sep,
    day =       7,
    abstract =  {This document describes the use of HDLC for framing PPP encapsulated packets. {[}STANDARDS-TRACK{]}},
}