Reference

Günther Steinbrück, Martin Schlegel, Ilse Dahlström, Bernd Röttger (1986): Characterization of Interspecific Hybrids Between Orchis mascula and O. pallens (Orchidaceae) by Enzyme Electrophoresis – Österreichische Botanische Zeitschrift = Plant Systematics and Evolution – 153: 229 - 241.