%% You should probably cite rfc7529 instead of this I-D.
@techreport{ietf-calext-rscale-03,
	number =	{draft-ietf-calext-rscale-03},
	type =		{Internet-Draft},
	institution =	{Internet Engineering Task Force},
	publisher =	{Internet Engineering Task Force},
	note =		{Work in Progress},
	url =		{https://datatracker.ietf.org/doc/html/draft-ietf-calext-rscale-03},
        author =	{Cyrus Daboo and Gregory Yakushev},
	title =		{{Non-Gregorian Recurrence Rules in iCalendar}},
	pagetotal =	19,
	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 document defines extensions to iCalendar (RFC 5545) to support use of non-Gregorian recurrence rules. It also defines how CalDAV (RFC 4791) servers and clients can be extended to support these new recurrence rules.},
}