%% You should probably cite rfc6497 instead of this I-D.
@techreport{davis-t-langtag-ext-07,
    number =    {draft-davis-t-langtag-ext-07},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-davis-t-langtag-ext/07/},
    author =    {Mark Davis and Courtney Falk and Addison Phillips and Yoshito Umaoka},
    title =     {{BCP 47 Extension T - Transformed Content}},
    pagetotal = 15,
    year =      2011,
    month =     dec,
    day =       5,
    abstract =  {This document specifies an Extension to BCP 47 that provides subtags for specifying the source language or script of transformed content, including content that has been transliterated, transcribed, or translated, or in some other way influenced by the source. It also provides for additional information used for identification. This document is not an Internet Standards Track specification; it is published for informational purposes.},
}