%% You should probably cite rfc8141 instead of this I-D.
@techreport{ietf-urnbis-rfc2141bis-urn-02,
    number =    {draft-ietf-urnbis-rfc2141bis-urn-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-ietf-urnbis-rfc2141bis-urn/02/},
    author =    {Alfred Hoenes},
    title =     {{Uniform Resource Name (URN) Syntax}},
    pagetotal = 32,
    year =      2012,
    month =     mar,
    day =       12,
    abstract =  {Uniform Resource Names (URNs) are intended to serve as persistent, location-independent, resource identifiers. This document serves as the foundation of the 'urn' URI Scheme according to RFC 3986 and sets forward the canonical syntax for URNs, which subdivides URNs into "namespaces". A discussion of both existing legacy and new namespaces and requirements for URN presentation and transmission are presented. Finally, there is a discussion of URN equivalence and how to determine it. This document supersedes RFC 2141. The requirements and procedures for URN Namespace registration documents are set forth in BCP 66, for which RFC 3406bis is the companion revised specification document replacing RFC 3406.},
}