%% You should probably cite rfc6947 instead of this I-D.
@techreport{boucadair-mmusic-altc-04,
    number =    {draft-boucadair-mmusic-altc-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-boucadair-mmusic-altc/04/},
    author =    {Mohamed Boucadair and Hadriel Kaplan and Robert Gilman and Simo Veikkolainen},
    title =     {{Session Description Protocol (SDP) Alternate Connectivity (ALTC) Attribute}},
    pagetotal = 14,
    year =      ** No value found for 'doc.pub_date.year' **,
    month =     ** No value found for 'doc.pub_date' **,
    day =       ** No value found for 'doc.pub_date.day' **,
    abstract =  {This document proposes a mechanism which allows to carry multiple IP addresses, of different address families (e.g., IPv4, IPv6), in the same SDP offer. The proposed attribute solves the backward compatibility problem which plagued ANAT, due to its syntax.},
}