"Ullman, W. (1968). A history of political thought: The middle ages. Penguin books.
Chicago Style (17th ed.) Citation"Ullman, Walter". A History of Political Thought: The Middle Ages. Penguin books, 1968.
MLA (9th ed.) Citation"Ullman, Walter". A History of Political Thought: The Middle Ages. Penguin books, 1968.
Warning: These citations may not always be 100% accurate.