Não informado. (1961). Illinois agricultural economics. University of Illinois, Department of Agricultural Economics.
Chicago-Zitierstil (17. Ausg.)Não informado. Illinois Agricultural Economics. Urbana, Ill: University of Illinois, Department of Agricultural Economics, 1961.
MLA-Zitierstil (8. Ausg.)Não informado. Illinois Agricultural Economics. University of Illinois, Department of Agricultural Economics, 1961.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.