APA (7th ed.) Citation

Langford, G. (1957). Alias O. Henry: A biography of William Sidney Porter. Macmillan.

Chicago Style (17th ed.) Citation

Langford, Gerald. Alias O. Henry: A Biography of William Sidney Porter. New York: Macmillan, 1957.

MLA (8th ed.) Citation

Langford, Gerald. Alias O. Henry: A Biography of William Sidney Porter. Macmillan, 1957.