%% You should probably cite draft-ietf-core-stateless instead of this I-D.
@techreport{hartke-core-stateless-02,
    number =    {draft-hartke-core-stateless-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-hartke-core-stateless/02/},
    author =    {Klaus Hartke},
    title =     {{Extended Tokens and Stateless Clients in the Constrained Application Protocol (CoAP)}},
    pagetotal = 16,
    year =      2018,
    month =     oct,
    day =       22,
    abstract =  {This document provides considerations for alleviating CoAP clients and intermediaries of maintaining per-request state. Additionally, it introduces a new, optional CoAP protocol extension for extended token lengths. This document updates RFCs 7252 and 8323.},
}