Reference

P. Arduino, Federica Verra, Rossella Cianchi, Walter Rossi, B. Corrias, Luciano Bullini (1996): Genetic variation and natural hybridization between Orchis laxiflora and Orchis palustris (Orchidaceae) – Österreichische Botanische Zeitschrift = Plant Systematics and Evolution – 202: 87 - 109.