Não informado. Virginia farm economics. Virginia Polytechnic Institute, Department of Agricultural Economics and Rural Sociology.
Chicago-referens (17:e uppl.)Não informado. Virginia Farm Economics. Blacksburg, Va: Virginia Polytechnic Institute, Department of Agricultural Economics and Rural Sociology.
MLA-referens (8:e uppl.)Não informado. Virginia Farm Economics. Virginia Polytechnic Institute, Department of Agricultural Economics and Rural Sociology.
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