APA引文

National Geographic Society (U.S.). Book Division. National Geographic guide to the national parks of the United States. National Geographic Society.

Chicago Style (17th ed.) Citation

National Geographic Society (U.S.). Book Division. National Geographic Guide to the National Parks of the United States. Washington, D.C.: National Geographic Society.

MLA引文

National Geographic Society (U.S.). Book Division. National Geographic Guide to the National Parks of the United States. National Geographic Society.

警告：這些引文格式不一定是100％准確.