@misc{rfc6067,
    series =    {Request for Comments},
    number =    6067,
    howpublished =  {RFC 6067},
    publisher = {RFC Editor},
    doi =       {10.17487/RFC6067},
    url =       {https://www.rfc-editor.org/info/rfc6067},
    author =    {Yoshito Umaoka and Addison Phillips and Mark Davis},
    title =     {{BCP 47 Extension U}},
    pagetotal = 8,
    year =      2010,
    month =     dec,
    abstract =  {This document specifies an Extension to BCP 47 that provides subtags that specify language and/or locale-based behavior or refinements to language tags, according to work done by the Unicode Consortium. This document is not an Internet Standards Track specification; it is published for informational purposes.},
}