Não informado. (1966). Index to selected outdoor recreation literature. U.S. Department of the Interior, Bureau of Outdoor Recreation.
Citação do estilo Chicago (17ª ed.)Não informado. Index to Selected Outdoor Recreation Literature. Washington: U.S. Department of the Interior, Bureau of Outdoor Recreation, 1966.
Citação MLA (8ª ed.)Não informado. Index to Selected Outdoor Recreation Literature. U.S. Department of the Interior, Bureau of Outdoor Recreation, 1966.
警告：这些引文格式不一定是100％准确.