Part of my research focuses on the description of non-Jewish calendars within medieval Hebrew treatises on the Jewish calendar. At the moment I am looking into the Muslim calendar. We find descriptions of its elements together with a conversion algorithm between the two calendars in Abraham bar Hiyya’s Sefer ha-Ibbur (12 c.), or alternatively, accompanied by conversion tables in Isaac Israeli’s Yesod Olam (14 c.). I would like to know whether there are other Hebrew sources, mainly pre-modern ones, which introduce the Muslim calendar and its relation to the Jewish calendar. To clarify, I am not interested in documents equating Muslim and Jewish dates (as seen in some of the Cairo Genizah materials), but rather, theoretical elaborations on the Muslim calendar.
Many thanks for your help.