%% You should probably cite rfc7529 instead of this I-D.
@techreport{ietf-calext-rscale-04,
    number =    {draft-ietf-calext-rscale-04},
    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-calext-rscale/04/},
    author =    {Cyrus Daboo and Gregory Yakushev},
    title =     {{Non-Gregorian Recurrence Rules in the Internet Calendaring and Scheduling Core Object Specification (iCalendar)}},
    pagetotal = 21,
    year =      2015,
    month =     feb,
    day =       11,
    abstract =  {This document defines extensions to the Internet Calendaring and Scheduling Core Object Specification (iCalendar) (RFC 5545) to support use of non-Gregorian recurrence rules. It also defines how Calendaring Extensions to WebDAV (CalDAV) (RFC 4791) servers and clients can be extended to support these new recurrence rules.},
}