International Union for Conservation of Nature and Natural Resources, National Park Service\nOrganization of American States\nEastern National Park and Monument Association. (1976). Parks. U.S. National Park Service.
Chicago-viite (17. p.)International Union for Conservation of Nature and Natural Resources, National Park Service\nOrganization of American States\nEastern National Park and Monument Association. Parks. Washington: U.S. National Park Service, 1976.
MLA-viite (8. p.)International Union for Conservation of Nature and Natural Resources, National Park Service\nOrganization of American States\nEastern National Park and Monument Association. Parks. U.S. National Park Service, 1976.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.