Não informado. (1966). Index to selected outdoor recreation literature. U.S. Department of the Interior, Bureau of Outdoor Recreation.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Index to Selected Outdoor Recreation Literature. Washington: U.S. Department of the Interior, Bureau of Outdoor Recreation, 1966.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Index to Selected Outdoor Recreation Literature. U.S. Department of the Interior, Bureau of Outdoor Recreation, 1966.
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