Gaarder, J. 1. (1996). Sophie's world: A novel about the history of philosophy. Berkley Books.
Lua i Stíl Chicago (17ú heag.)Gaarder, Jostein 1952. Sophie's World: A Novel About the History of Philosophy. New York: Berkley Books, 1996.
Lua MLA (9ú heag.)Gaarder, Jostein 1952. Sophie's World: A Novel About the History of Philosophy. Berkley Books, 1996.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.