- https://github.com/bmoeskau/Extensible/blob/master/recurrence-overview.md
- https://github.com/bakineggs/recurring_events_for
- https://vertabelo.com/blog/again-and-again-managing-recurring-events-in-a-data-model/
- https://datatracker.ietf.org/doc/html/rfc2445#section-4.8.5.4
- https://www.ical4j.org/examples/
- https://developers.google.com/calendar/api/concepts
- https://learn.microsoft.com/en-us/graph/api/resources/calendar?view=graph-rest-1.0
- https://learn.microsoft.com/en-us/previous-versions/office/developer/exchange-server-2010/dd633694(v=exchg.80)?redirectedfrom=MSDN
- https://www.youtube.com/watch?v=dOMW0WcvvRc