APA (7th ed.) Citation

Keen, M. H. (1965). The laws of war in the late Middle Ages. Routledge and K. Paul.

Chicago Style (17th ed.) Citation

Keen, Maurice Hugh. The Laws of War in the Late Middle Ages. London: Routledge and K. Paul, 1965.

MLA (9th ed.) Citation

Keen, Maurice Hugh. The Laws of War in the Late Middle Ages. Routledge and K. Paul, 1965.