Cita APA

Nature Conservancy, Nature Conservancy, United States. Department of the Interior. National Park Service. Office of the Chief Scientist, & United States. Department of the Interior. National Park Service. Office of the Chief Scientist. (1977). Preserving our natural heritage. [Washington, D.C.]: U.S. Government Printing Office.

Citación estilo Chicago

Nature Conservancy, Nature Conservancy, United States. Department of the Interior. National Park Service. Office of the Chief Scientist, y United States. Department of the Interior. National Park Service. Office of the Chief Scientist. Preserving Our Natural Heritage. [Washington, D.C.]: U.S. Government Printing Office, 1977.

Cita MLA

Nature Conservancy, Nature Conservancy, United States. Department of the Interior. National Park Service. Office of the Chief Scientist, y United States. Department of the Interior. National Park Service. Office of the Chief Scientist. Preserving Our Natural Heritage. [Washington, D.C.]: U.S. Government Printing Office, 1977.