Cita APA

National Geographic Society. Cartographic Division. (1978). The Heart of Grand Canyon: Grand Canyon National Park Arizona. Washington: The Society.

Citación estilo Chicago

National Geographic Society. Cartographic Division. The Heart of Grand Canyon: Grand Canyon National Park Arizona. Washington: The Society, 1978.

Cita MLA

National Geographic Society. Cartographic Division. The Heart of Grand Canyon: Grand Canyon National Park Arizona. Washington: The Society, 1978.