APA (7th ed.) Citation

GILBERT, P. W. (1939). Avian lung and air-sac system. Auk., 56, 57.

Chicago Style (17th ed.) Citation

GILBERT, Perry W. "Avian Lung and Air-sac System." Auk. 56 (1939): 57.

MLA (9th ed.) Citation

GILBERT, Perry W. "Avian Lung and Air-sac System." Auk., vol. 56, 1939, p. 57.