Christensen, J. R. (1981). A field guide to the butterflies of the Pacific Northwest. University Press of Idaho.
Chicago Style (17th ed.) CitationChristensen, James R. A Field Guide to the Butterflies of the Pacific Northwest. Moscow, Idaho: University Press of Idaho, 1981.
MLA (8th ed.) CitationChristensen, James R. A Field Guide to the Butterflies of the Pacific Northwest. University Press of Idaho, 1981.
Warning: These citations may not always be 100% accurate.