Não informado. (1946). Iowa farm science. Iowa State University of Science and Technology, Cooperative Extension Service.
Chicago-Zitierstil (17. Ausg.)Não informado. Iowa Farm Science. Ames, Iowa: Iowa State University of Science and Technology, Cooperative Extension Service, 1946.
MLA-Zitierstil (8. Ausg.)Não informado. Iowa Farm Science. Iowa State University of Science and Technology, Cooperative Extension Service, 1946.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.