Kearn, G.C. (1976)
Observations on monogenean parasites from the nasal fossae of European rays: Empruthotrema raiae (MacCallum, 1916), Johnston and Tiegs, 1922 and E. torpedinis sp. nov. from Torpedo marmorata. Proceedings of the Institute of Biology and Pedology, Far–East Science Centre, Vladivostock, USSR. 34: 45–54.(In Russian, with English summary).