Nisbet, J. (2012). David Douglas: A naturalist at work : an illustrated exploration across two centuries in the Pacific Northwest. Sasquatch Books.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNisbet, Jack. David Douglas: A Naturalist at Work : An Illustrated Exploration Across Two Centuries in the Pacific Northwest. Seattle, WA: Sasquatch Books, 2012.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNisbet, Jack. David Douglas: A Naturalist at Work : An Illustrated Exploration Across Two Centuries in the Pacific Northwest. Sasquatch Books, 2012.
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