%% You should probably cite rfc3880 instead of this I-D.
@techreport{ietf-iptel-cpl-09,
    number =    {draft-ietf-iptel-cpl-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-iptel-cpl/09/},
    author =    {Jonathan Lennox and Xiaotao Wu and Henning Schulzrinne},
    title =     {{Call Processing Language (CPL): A Language for User Control of Internet Telephony Services}},
    pagetotal = 74,
    year =      2004,
    month =     apr,
    day =       29,
    abstract =  {This document defines the Call Processing Language (CPL), a language to describe and control Internet telephony services. It is designed to be implementable on either network servers or user agents. It is meant to be simple, extensible, easily edited by graphical clients, and independent of operating system or signalling protocol. It is suitable for running on a server where users may not be allowed to execute arbitrary programs, as it has no variables, loops, or ability to run external programs. {[}STANDARDS-TRACK{]}},
}