Cita APA (7a ed.)
National Geographic Society (U.S.). National geographic world. [National Geographic Society].
Cita Chicago Style (17a ed.)
National Geographic Society (U.S.). National Geographic World. [Washington]: [National Geographic Society].
Cita MLA (9a ed.)
National Geographic Society (U.S.). National Geographic World. [National Geographic Society].
Precaución: Estas citas no son 100% exactas.