APA استشهاد

Ullmann, W. (1965). History of Political Thought: The Middle Ages. Penguin.

استشهاد بنمط شيكاغو

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

MLA استشهاد

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