Cita APA (7th ed.)
Gaarder, J., & Moller, P. (1995). Sophie's world: A novel about the history of philosophy. Phoenix.
Cita Chicago (17th ed.)
Gaarder, Jostein, i Paulette Moller. Sophie's World: A Novel About the History of Philosophy. London: Phoenix, 1995.
Cita MLA (9th ed.)
Gaarder, Jostein, i Paulette Moller. Sophie's World: A Novel About the History of Philosophy. Phoenix, 1995.
Atenció: Aquestes cites poden no estar 100% correctes.