Rix (Boiss.) 1978 - Heywood VH (1978) Flora Europaea: Notulae Systematicae ad Floram Europaeam spectantes: No. 20. Botanical Journal of the Linnean Society 76(4): 297-384. doi: 10.1111/j.1095-8339.1978.tb01817.x.
There is no corrections for Fritillaria graeca subsp. thessala yet.