See https://tools.ietf.org/html/rfc5545#section-3.3.10 for a technical description or the alternative is to create some events in JEvents by hand with the repeat patterns you are looking to use and create an export out of JEvents and see how it has set the RRULE value.
Hi Geraint, thanks for your answer. I've already tested (after a few missteps...) the export of a few events (single day, multiday, recurring...) but this results in an .ics file , instead I was trying to import a CSV file, and without any content in te "RRUL" column I can't import any event.
Maybe it's just me failing, but I would like to see some specs on the possible content of each column and what will the import result be.
Cheers
Luigi