Não informado. Virginia farm economics. Virginia Polytechnic Institute, Department of Agricultural Economics and Rural Sociology.
Lua i Stíl Chicago (17ú heag.)Não informado. Virginia Farm Economics. Blacksburg, Va: Virginia Polytechnic Institute, Department of Agricultural Economics and Rural Sociology.
Lua MLA (8ú heag.)Não informado. Virginia Farm Economics. Virginia Polytechnic Institute, Department of Agricultural Economics and Rural Sociology.
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