APA (7th ed.) Citation

Macquarrie, J. (1973). Existentialism. Penguin Books.

Chicago Style (17th ed.) Citation

Macquarrie, John. Existentialism. Harmondsworth: Penguin Books, 1973.

MLA (9th ed.) Citation

Macquarrie, John. Existentialism. Penguin Books, 1973.