APA (7th ed.) Citation

Runciman, S. (1951). A history of the Crusades. University Press.

Chicago Style (17th ed.) Citation

Runciman, Steven. A History of the Crusades. Cambridge, [Eng.]: University Press, 1951.

MLA (9th ed.) Citation

Runciman, Steven. A History of the Crusades. University Press, 1951.