Citazione Stile APA (7a Edizione)

Ralph, P. L. (1997). World civilizations, their history and their culture (9th ed.). W.W. Norton.

Citazione stile Chigago Style (17a edizione)

Ralph, Philip Lee. World Civilizations, Their History and Their Culture. 9th ed. New York: W.W. Norton, 1997.

Citatione MLA (8a ed.)

Ralph, Philip Lee. World Civilizations, Their History and Their Culture. 9th ed. W.W. Norton, 1997.