Não informado. Extension bulletin. Purdue University, Department of Agricultural Extension.
Chicago-Zitierstil (17. Ausg.)Não informado. Extension Bulletin. Lafayette, Ind: Purdue University, Department of Agricultural Extension.
MLA-Zitierstil (8. Ausg.)Não informado. Extension Bulletin. Purdue University, Department of Agricultural Extension.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.