Heller, R. (2000). Bill Gates. Dorling Kindersley.
Cita Chicago (17th ed.)Heller, Robert. Bill Gates. London: Dorling Kindersley, 2000.
Cita MLA (9th ed.)Heller, Robert. Bill Gates. Dorling Kindersley, 2000.
Atenció: Aquestes cites poden no estar 100% correctes.