Não informado. (1980). Soil and water conservation news. U.S. Department of Agriculture, Soil Conservation Service.
Chicago (17e ed.) BronvermeldingNão informado. Soil and Water Conservation News. Washington: U.S. Department of Agriculture, Soil Conservation Service, 1980.
MLA (8e ed.) BronvermeldingNão informado. Soil and Water Conservation News. U.S. Department of Agriculture, Soil Conservation Service, 1980.
Let op: Deze citaties zijn niet altijd 100% accuraat.