Reference Base Butorphanol and azaperone as a safe alternative for repea...
Radcliffe, R.W.; Ferrell, S.T.; Childs, S.E., 2000. Butorphanol and azaperone as a safe alternative for repeated chemical restraint in captive white rhinoceros (Ceratotherium simum). Journal of Zoo and Wildlife Medicine 31 (2): 196-200, tables 1-2