APA (7th ed.) Citation

Simpson, G. G. (1961). Principles of animal taxonomy. Columbia Univ. Press.

Chicago Style (17th ed.) Citation

Simpson, George Gaylord. Principles of Animal Taxonomy. New York: Columbia Univ. Press, 1961.

MLA (9th ed.) Citation

Simpson, George Gaylord. Principles of Animal Taxonomy. Columbia Univ. Press, 1961.