Tyteca, Daniel, Manon Ceinos, Jean-Louis Gathoye, Rein Brys, and Hans Jacquemyn. 2012. “On the Morphological, Biological and Genetic Heterogeneity of the Genus Orchis (Orchidaceae, Orchidinae)”. Phytotaxa 75 (1). Auckland, New Zealand:19–32. https://doi.org/10.11646/phytotaxa.75.1.2.