APA

National Education Association, U.S. Department of the Interior. National Park Service, . (1972). A Guide to Planning and Conducting Environmental Study Area Workshops. Washington, D.C: National Park Service.

Chicago

National Education Association, U.S. Department of the Interior. National Park Service, . 1972. A Guide to Planning and Conducting Environmental Study Area Workshops. Washington, D.C: National Park Service.

Harvard

National Education Association, U.S. Department of the Interior. National Park Service, . (1972). A Guide to Planning and Conducting Environmental Study Area Workshops. Washington, D.C: National Park Service.

MLA

National Education Association, U.S. Department of the Interior. National Park Service, . A Guide to Planning and Conducting Environmental Study Area Workshops. Washington, D.C: National Park Service. 1972.