Cita APA (7a ed.)

Gaarder, J., & Moller, P. (1996). Sophie's world: A novel about the history of philosophy. Phoenix.

Cita Chicago Style (17a ed.)

Gaarder, Jostein, y Paulette Moller. Sophie's World: A Novel About the History of Philosophy. London: Phoenix, 1996.

Cita MLA (9a ed.)

Gaarder, Jostein, y Paulette Moller. Sophie's World: A Novel About the History of Philosophy. Phoenix, 1996.