Ehrend. (Boiss. & Heldr.) 1975 - Heywood VH (1975) Flora Europaea: Notulae Systematicae ad Floram Europaeam spectantes: No. 17. Botanical Journal of the Linnean Society 71(1): 39-50. doi: 10.1111/j.1095-8339.1975.tb00937.x.
There is no corrections for Knautia drymeia subsp. nympharum yet.