APA (7th ed.) Citation

National Geographic Society (U.S.). (2011). National Geographic guide to state parks of the United States and Canadian provincial parks (4th edition.). National Geographic.

Chicago Style (17th ed.) Citation

National Geographic Society (U.S.). National Geographic Guide to State Parks of the United States and Canadian Provincial Parks. 4th edition. Washington, D.C: National Geographic, 2011.

MLA (9th ed.) Citation

National Geographic Society (U.S.). National Geographic Guide to State Parks of the United States and Canadian Provincial Parks. 4th edition. National Geographic, 2011.