Não informado. (1961). Illinois agricultural economics. University of Illinois, Department of Agricultural Economics.
Chicagoスタイル(17版)引用形式Não informado. Illinois Agricultural Economics. Urbana, Ill: University of Illinois, Department of Agricultural Economics, 1961.
MLA(8版)引用形式Não informado. Illinois Agricultural Economics. University of Illinois, Department of Agricultural Economics, 1961.
警告: この引用は必ずしも正確ではありません.