Cita APA (7th ed.)
ebrary, Inc. (1993). Protecting visibility in national parks and wilderness areas. National Academy Press.
Cita Chicago (17th ed.)
ebrary, Inc. Protecting Visibility in National Parks and Wilderness Areas. Washington, D.C.: National Academy Press, 1993.
Cita MLA (9th ed.)
ebrary, Inc. Protecting Visibility in National Parks and Wilderness Areas. National Academy Press, 1993.
Atenció: Aquestes cites poden no estar 100% correctes.