Não informado. US Forest Service Research Note PNW. U.S. Forest Service.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. US Forest Service Research Note PNW. Portland, Ore: U.S. Forest Service.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. US Forest Service Research Note PNW. U.S. Forest Service.
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