APA (7th ed.) Citation

Runciman, S. (1952). A history of the crusades. Penguin Books.

Chicago Style (17th ed.) Citation

Runciman, Steven. A History of the Crusades. England: Penguin Books, 1952.

MLA (9th ed.) Citation

Runciman, Steven. A History of the Crusades. Penguin Books, 1952.

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