APA (7th ed.) Citation

Boulenger, E. G., & Wilson, M. C. J. (1948). Zoo animals. Penguin.

Chicago Style (17th ed.) Citation

Boulenger, E. G., and Maurice Charles John Wilson. Zoo Animals. West Drayton: Penguin, 1948.

MLA (9th ed.) Citation

Boulenger, E. G., and Maurice Charles John Wilson. Zoo Animals. Penguin, 1948.