BITTNER, A. & LANG, S. (1980)
Some aspects of the osmoregulation of Amazonian freshwater stingrays (Potamotrygon hystrix)-I. Serum osmolality, sodium and chloride content, water content, hematocrit and urea level. Comparative Biochemistry and Physiology – Part A, Physiology, 67 (1): 9–13
DOI: 10.1016/0300-9629(80)90402-8