Não informado. (1966). Index to selected outdoor recreation literature. U.S. Department of the Interior, Bureau of Outdoor Recreation.
Chicago-Zitierstil (17. Ausg.)Não informado. Index to Selected Outdoor Recreation Literature. Washington: U.S. Department of the Interior, Bureau of Outdoor Recreation, 1966.
MLA-Zitierstil (8. Ausg.)Não informado. Index to Selected Outdoor Recreation Literature. U.S. Department of the Interior, Bureau of Outdoor Recreation, 1966.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.