APA (7th ed.) Citation

Não informado. (1991). Research and Exploration. National Geographic Society.

Chicago Style (17th ed.) Citation

Não informado. Research and Exploration. Gaithersburg, Md: National Geographic Society, 1991.

MLA (8th ed.) Citation

Não informado. Research and Exploration. National Geographic Society, 1991.

Warning: These citations may not always be 100% accurate.