Cita APA (7a ed.)

Estados Unidos. Department of the Interior. National Park Service. (1941). A study of the park and recreation problem of the United States. Department of the Interior.

Cita Chicago Style (17a ed.)

Estados Unidos. Department of the Interior. National Park Service. A Study of the Park and Recreation Problem of the United States. Washington: Department of the Interior, 1941.

Cita MLA (8a ed.)

Estados Unidos. Department of the Interior. National Park Service. A Study of the Park and Recreation Problem of the United States. Department of the Interior, 1941.