Não informado. (2012). Purdue Agriculture Reports. Purdue University, Agricultural Experiment Station.
Chicago-referens (17:e uppl.)Não informado. Purdue Agriculture Reports. West Lafayette, Ind: Purdue University, Agricultural Experiment Station, 2012.
MLA-referens (8:e uppl.)Não informado. Purdue Agriculture Reports. Purdue University, Agricultural Experiment Station, 2012.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.