Não informado. (2007). Report of the Iowa Agricultural Experiment Station for de two years. Agricultural Experiment Station.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Report of the Iowa Agricultural Experiment Station for De Two Years. Ames, Iowa: Agricultural Experiment Station, 2007.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Report of the Iowa Agricultural Experiment Station for De Two Years. Agricultural Experiment Station, 2007.
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