National Geographic Society (U.S.). Special Publications Division. (1988). America's hidden wilderness: Lands of seclusion. The Society.
Chicago-referens (17:e uppl.)National Geographic Society (U.S.). Special Publications Division. America's Hidden Wilderness: Lands of Seclusion. Washington, D.C: The Society, 1988.
MLA-referens (9:e uppl.)National Geographic Society (U.S.). Special Publications Division. America's Hidden Wilderness: Lands of Seclusion. The Society, 1988.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.