APA

Endler J. A., . (1977). Geographic variation, speciation, and clines. Princeton, New Jersey: Princeton University Press.

Chicago

Endler John A, . 1977. Geographic variation, speciation, and clines. Princeton, New Jersey: Princeton University Press.

Harvard

Endler J. A., . (1977). Geographic variation, speciation, and clines. Princeton, New Jersey: Princeton University Press.

MLA

Endler John A, . Geographic variation, speciation, and clines. Princeton, New Jersey: Princeton University Press. 1977.