APA (7th ed.) Citation

Barker, E. (1923). The crusades. Oxford Univ. Press.

Chicago Style (17th ed.) Citation

Barker, Ernest. The Crusades. London: Oxford Univ. Press, 1923.

MLA (9th ed.) Citation

Barker, Ernest. The Crusades. Oxford Univ. Press, 1923.

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