Não informado. (1946). Iowa farm science. Iowa State University of Science and Technology, Cooperative Extension Service.
Čikaški stil citiranja (17. izdanje)Não informado. Iowa Farm Science. Ames, Iowa: Iowa State University of Science and Technology, Cooperative Extension Service, 1946.
MLA način citiranja (8. izdanje)Não informado. Iowa Farm Science. Iowa State University of Science and Technology, Cooperative Extension Service, 1946.
Upozorenje: Ovi citati možda nisu uvijek 100% točni.