%% You should probably cite rfc7809 instead of this I-D.
@techreport{ietf-tzdist-caldav-timezone-ref-03,
    number =    {draft-ietf-tzdist-caldav-timezone-ref-03},
    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-tzdist-caldav-timezone-ref/03/},
    author =    {Cyrus Daboo},
    title =     {{CalDAV: Time Zones by Reference}},
    pagetotal = 12,
    year =      2015,
    month =     jun,
    day =       12,
    abstract =  {This document defines an extension to the CalDAV calendar access protocol to allow clients and servers to exchange iCalendar data without the need to send full time zone data.},
}