Cita APA

National Geographic Society, & National Geographic Society. (2008). Guide to the state parks of the United States (3. edition.). Washington, D.C.: National Geographic.

Citación estilo Chicago

National Geographic Society, y National Geographic Society. Guide to the State Parks of the United States. 3. edition. Washington, D.C.: National Geographic, 2008.

Cita MLA

National Geographic Society, y National Geographic Society. Guide to the State Parks of the United States. 3. edition. Washington, D.C.: National Geographic, 2008.