%% You should probably cite draft-levkowetz-xml2rfc-v3-implementation-notes-13 instead of this revision.
@techreport{levkowetz-xml2rfc-v3-implementation-notes-09,
    number =    {draft-levkowetz-xml2rfc-v3-implementation-notes-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-levkowetz-xml2rfc-v3-implementation-notes/09/},
    author =    {Henrik Levkowetz},
    title =     {{Implementation notes for RFC7991,
"The 'xml2rfc' Version 3 Vocabulary"}},
    pagetotal = 54,
    year =      ** No value found for 'doc.pub_date.year' **,
    month =     ** No value found for 'doc.pub_date' **,
    day =       ** No value found for 'doc.pub_date.day' **,
    abstract =  {This memo documents issues and observations found while implementing RFC 7991. Individual notes are organised into separate sections, depending on their character.},
}