Hooft, G. '. (2008). Playing with planets (English ed.). World Scientific.
Cita Chicago (17th ed.)Hooft, G. 't. Playing with Planets. English ed. Hackensack, NJ: World Scientific, 2008.
Cita MLA (9th ed.)Hooft, G. 't. Playing with Planets. English ed. World Scientific, 2008.
Atenció: Aquestes cites poden no estar 100% correctes.