APA (7th ed.) Citation

Whittaker, W. G. (1940). Collected essays. Oxford university press.

Chicago Style (17th ed.) Citation

Whittaker, W. G. Collected Essays. London, New York [etc.]: Oxford university press, 1940.

MLA (9th ed.) Citation

Whittaker, W. G. Collected Essays. Oxford university press, 1940.