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.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.