APA (7th ed.) Zitazioa

Ullmann, W. (1965). A history of political thought: The middle ages. Penguin.

Chicago Style (17th ed.) Zitazioa

Ullmann, Walter. A History of Political Thought: The Middle Ages. Harmondsworth: Penguin, 1965.

MLA (9th ed.) Zitazioa

Ullmann, Walter. A History of Political Thought: The Middle Ages. Penguin, 1965.