%% You should probably cite rfc5924 instead of this I-D.
@techreport{ietf-sip-eku-08,
    number =    {draft-ietf-sip-eku-08},
    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-sip-eku/08/},
    author =    {Scott Lawrence and Vijay K. Gurbani},
    title =     {{Extended Key Usage (EKU) for Session Initiation Protocol (SIP) X.509 Certificates}},
    pagetotal = 8,
    year =      2009,
    month =     oct,
    day =       20,
    abstract =  {This memo documents an extended key usage (EKU) X.509 certificate extension for restricting the applicability of a certificate to use with a Session Initiation Protocol (SIP) service. As such, in addition to providing rules for SIP implementations, this memo also provides guidance to issuers of certificates for use with SIP. This document defines an Experimental Protocol for the Internet community.},
}