Cita APA (7th ed.)

Gaarder, J. 1. (1996). Sophie's world: A novel about the history of philosophy. Berkley Books.

Cita Chicago (17th ed.)

Gaarder, Jostein 1952. Sophie's World: A Novel About the History of Philosophy. New York: Berkley Books, 1996.

Cita MLA (9th ed.)

Gaarder, Jostein 1952. Sophie's World: A Novel About the History of Philosophy. Berkley Books, 1996.