Não informado. Virginia agricultural economics. Virginia Polytechnic Institute, Department of Agricultural Economics and Rural Sociology.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Virginia Agricultural Economics. Blacksburg, Va: Virginia Polytechnic Institute, Department of Agricultural Economics and Rural Sociology.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Virginia Agricultural Economics. Virginia Polytechnic Institute, Department of Agricultural Economics and Rural Sociology.
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