Não informado. (1935). Soil conservation. U.S. Department of Agriculture, Soil Conservation Service.
Chicagoスタイル(17版)引用形式Não informado. Soil Conservation. Washington: U.S. Department of Agriculture, Soil Conservation Service, 1935.
MLA(8版)引用形式Não informado. Soil Conservation. U.S. Department of Agriculture, Soil Conservation Service, 1935.
警告: この引用は必ずしも正確ではありません.