When does a foreign species deserve a "permit of residence"? Non-indigenous species (NIS): examples of varying exoticness and varying immigration age, taken from herpetology
W. Bohme, When does a foreign species deserve a "permit of residence"? Non-indigenous species (NIS): examples of varying exoticness and varying immigration age, taken from herpetology, ETHOL ECOL, 12(3), 2000, pp. 326-328