%% You should probably cite draft-shelby-core-coap instead of this I-D.
@techreport{shelby-6lowapp-coap-00,
    number =    {draft-shelby-6lowapp-coap-00},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-shelby-6lowapp-coap/00/},
    author =    {Zach Shelby and Michael Stuber and Don Sturek and Brian Frank and Richard Kelsey},
    title =     {{CoAP Feature Analysis}},
    pagetotal = 16,
    year =      2009,
    month =     dec,
    day =       23,
    abstract =  {This document considers the requirements and resulting features needed for the design of the Constrained Application Protocol (CoAP). Starting from requirements for energy and building automation applications, the basic features are identified along with an analysis of possible realizations. The goal of the document is to provide a basis for protocol design and related discussion.},
}