APA (7th ed.) Citation

Keck, D. (1998). Angels & angelology in the Middle Ages. Oxford University Press.

Chicago Style (17th ed.) Citation

Keck, David. Angels & Angelology in the Middle Ages. New York: Oxford University Press, 1998.

MLA (9th ed.) Citation

Keck, David. Angels & Angelology in the Middle Ages. Oxford University Press, 1998.