Thorson, T.B. & Langhammer, J.K. & Oetinger, M.I. (1988)
Periodic shedding and replacement of venomous caudal spines, with special reference to South American freshwater stingrays, Potamotrygon spp. Environmental Biology of Fishes, 23(4), 299–314
DOI: 10.1007/BF00005241
Thorson, T.B. & Langhammer, J.K. & Oetinger, M.I. (1983)
Reproduction and development of the South American freshwater stingrays, Potamotrygon circularis and P. motoro. Environmental Biology of Fishes, 9(1), 3–24
DOI: 10.1007/BF00001055