Não informado. (1935). Soil conservation. U.S. Department of Agriculture, Soil Conservation Service.
Style de citation Chicago (17e éd.)Não informado. Soil Conservation. Washington: U.S. Department of Agriculture, Soil Conservation Service, 1935.
Style de citation MLA (8e éd.)Não informado. Soil Conservation. U.S. Department of Agriculture, Soil Conservation Service, 1935.
Attention : ces citations peuvent ne pas être correctes à 100%.