%% You should probably cite rfc6924 instead of this I-D.
@techreport{leiba-urnbis-ietf-namespace-02,
    number =    {draft-leiba-urnbis-ietf-namespace-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-leiba-urnbis-ietf-namespace/02/},
    author =    {Barry Leiba},
    title =     {{Registration of Second-Level URN Namespaces under "ietf"}},
    pagetotal = 4,
    year =      2013,
    month =     feb,
    day =       14,
    abstract =  {RFC 2648 defines the "ietf" URN namespace and a number of sub- namespaces. RFC 3553 defines an additional sub-namespace, "params", and creates a registry to document allocations under that. But there is no registry that lists, in one place, all sub-namespaces of "ietf". This document creates and populates such a registry, thereby changing the mechanism defined in RFC 2648 for adding new sub- namespaces of "ietf".},
}