National Geographic Society. (2015). Answer book: 10,001 fast facts about our world. National Geographic Society.
Cita Chicago (17th ed.)National Geographic Society. Answer Book: 10,001 Fast Facts About Our World. Washington, D.C.: National Geographic Society, 2015.
Cita MLA (9th ed.)National Geographic Society. Answer Book: 10,001 Fast Facts About Our World. National Geographic Society, 2015.
Atenció: Aquestes cites poden no estar 100% correctes.