APA (7th ed.) Citation

Macquarrie, J. (1973). Existentialism: An introduction, guide and assessment. Penguin.

Chicago Style (17th ed.) Citation

Macquarrie, John. Existentialism: An Introduction, Guide and Assessment. London: Penguin, 1973.

MLA (9th ed.) Citation

Macquarrie, John. Existentialism: An Introduction, Guide and Assessment. Penguin, 1973.