Não informado. AERR. University of Illinois at Urbana-Champaign, Agricultural Experiment Station.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. AERR. Urbana, Ill: University of Illinois at Urbana-Champaign, Agricultural Experiment Station.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. AERR. University of Illinois at Urbana-Champaign, Agricultural Experiment Station.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.