APA (7e ed.) Bronvermelding

National Geographic Society. (1999). The National Geographic desk reference: A geographical reference with hundreds of photographs, maps, charts, and graphs. National Geographic Society.

Chicago (17e ed.) Bronvermelding

National Geographic Society. The National Geographic Desk Reference: A Geographical Reference with Hundreds of Photographs, Maps, Charts, and Graphs. Washington, D.C: National Geographic Society, 1999.

MLA (9e ed.) Bronvermelding

National Geographic Society. The National Geographic Desk Reference: A Geographical Reference with Hundreds of Photographs, Maps, Charts, and Graphs. National Geographic Society, 1999.