APA (7th ed.) Zitazioa
ebrary, Inc. (1993). Protecting visibility in national parks and wilderness areas. National Academy Press.
Chicago Style (17th ed.) Zitazioa
ebrary, Inc. Protecting Visibility in National Parks and Wilderness Areas. Washington, D.C.: National Academy Press, 1993.
MLA (9th ed.) Zitazioa
ebrary, Inc. Protecting Visibility in National Parks and Wilderness Areas. National Academy Press, 1993.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.