LASSO, C.A. & RIAL, B.A. & LASSO-ALCALA, O. (1997)
Notes on the biology of the freshwater stingrays Paratrygon aiereba (Müller & Henle, 1841) and Potamotrygon orbignyi (Castelnau, 1855) (Chondrichthyes: Potamotrygonidae) in the Venezuelan Llanos. Aqua, International Journal of Ichthyology, 2 (3): 39–50