Não informado. (1946). Iowa farm science. Iowa State University of Science and Technology, Cooperative Extension Service.
Cita Chicago Style (17a ed.)Não informado. Iowa Farm Science. Ames, Iowa: Iowa State University of Science and Technology, Cooperative Extension Service, 1946.
Cita MLA (8a ed.)Não informado. Iowa Farm Science. Iowa State University of Science and Technology, Cooperative Extension Service, 1946.
Precaución: Estas citas no son 100% exactas.