Christensen, J. R. (1981). A field guide to the butterflies of the Pacific Northwest. University Press of Idaho.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रChristensen, James R. A Field Guide to the Butterflies of the Pacific Northwest. Moscow, Idaho: University Press of Idaho, 1981.
एमएलए (8वां संस्करण) प्रशस्ति पत्रChristensen, James R. A Field Guide to the Butterflies of the Pacific Northwest. University Press of Idaho, 1981.
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