APA (7th ed.) Citation

Whalen, B. E. (2019). The two powers: The papacy, the empire, and the struggle for sovereignty in the thirteenth century. PENN, University of Pennsylvania Press.

Chicago Style (17th ed.) Citation

Whalen, Brett Edward. The Two Powers: The Papacy, the Empire, and the Struggle for Sovereignty in the Thirteenth Century. Philadelphia: PENN, University of Pennsylvania Press, 2019.

MLA (8th ed.) Citation

Whalen, Brett Edward. The Two Powers: The Papacy, the Empire, and the Struggle for Sovereignty in the Thirteenth Century. PENN, University of Pennsylvania Press, 2019.