Não informado. (1971). Forestry Research Newsletter. Great Lakes Forest Research Centre.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Forestry Research Newsletter. Sault Ste. Marie, Canada: Great Lakes Forest Research Centre, 1971.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Forestry Research Newsletter. Great Lakes Forest Research Centre, 1971.
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