Não informado. (2018). Research Report. Virginia Agricultural Experiment Station, Virginia Polytechnic Institute.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Research Report. Blacksburg, Va: Virginia Agricultural Experiment Station, Virginia Polytechnic Institute, 2018.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Research Report. Virginia Agricultural Experiment Station, Virginia Polytechnic Institute, 2018.
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