APA (7th ed.) Citation

Doherty, G. (2011). The secret crusade. Penguin Books.

Chicago Style (17th ed.) Citation

Doherty, Gordon. The Secret Crusade. London: Penguin Books, 2011.

MLA (9th ed.) Citation

Doherty, Gordon. The Secret Crusade. Penguin Books, 2011.

Warning: These citations may not always be 100% accurate.