Não informado. (1946). Iowa farm science. Iowa State University of Science and Technology, Cooperative Extension Service.
Chicago (17e ed.) BronvermeldingNão informado. Iowa Farm Science. Ames, Iowa: Iowa State University of Science and Technology, Cooperative Extension Service, 1946.
MLA (8e ed.) BronvermeldingNão informado. Iowa Farm Science. Iowa State University of Science and Technology, Cooperative Extension Service, 1946.
Let op: Deze citaties zijn niet altijd 100% accuraat.