APA (7th ed.) Citation

Calkins, G. N. (1926). The biology of the Protozoa. Lea & Febiger.

Chicago Style (17th ed.) Citation

Calkins, Gary N. The Biology of the Protozoa. Philadelphia, New York: Lea & Febiger, 1926.

MLA (9th ed.) Citation

Calkins, Gary N. The Biology of the Protozoa. Lea & Febiger, 1926.