Ullmann, W. (1965). History of Political Thought: The Middle Ages. Penguin.
शिकागो स्टाइल उद्धरणUllmann, Walter. History of Political Thought: The Middle Ages. England: Penguin, 1965.
एमएलए उद्धरणUllmann, Walter. History of Political Thought: The Middle Ages. Penguin, 1965.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.