APA (7th ed.) Citation

Hemingway, E. (1964). A farewell to arms. Penguin Books.

Chicago Style (17th ed.) Citation

Hemingway, Ernest. A Farewell to Arms. Harmondsworth [etc.]: Penguin Books, 1964.

MLA (9th ed.) Citation

Hemingway, Ernest. A Farewell to Arms. Penguin Books, 1964.