Isaac, L. A. (1949). Better Douglas fir forests from better seed. University of Washington Press.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रIsaac, Leo A. Better Douglas Fir Forests from Better Seed. Seattle: University of Washington Press, 1949.
एमएलए (8वां संस्करण) प्रशस्ति पत्रIsaac, Leo A. Better Douglas Fir Forests from Better Seed. University of Washington Press, 1949.
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