APA (7th ed.) Citation

Smith, M. J. (1966). The theory of evolution (2nd ed.). Penguin Books.

Chicago Style (17th ed.) Citation

Smith, Maynard J. The Theory of Evolution. 2nd ed. Baltimore: Penguin Books, 1966.

MLA (9th ed.) Citation

Smith, Maynard J. The Theory of Evolution. 2nd ed. Penguin Books, 1966.