Não informado. (1935). Soil conservation. U.S. Department of Agriculture, Soil Conservation Service.
Čikaški stil citiranja (17. izdanje)Não informado. Soil Conservation. Washington: U.S. Department of Agriculture, Soil Conservation Service, 1935.
MLA način citiranja (8. izdanje)Não informado. Soil Conservation. U.S. Department of Agriculture, Soil Conservation Service, 1935.
Upozorenje: Ovi citati možda nisu uvijek 100% točni.