Funded by the National Science Foundation PEET program (Partnerships for Enhancing Expertise in Taxonomy)
Dewey, J. E., and C. E. Carlson. 1980. Northern Region (R-1). Pages 3-11 in P. W. Orr and H. D. Brown, Forest insect and disease conditions in the United States, 1978. United States Department of Agriculture, Forest Service. vi + 83 p.