Funded by the National Science Foundation PEET program (Partnerships for Enhancing Expertise in Taxonomy)
Acciavatti, R. E., and J. W. Walters. 1977. Southwestern States (R-3). Pages 35-40 in H. V. Toko and K. H. Knauer, Forest insect and disease conditions in the United States, 1975. United States Department of Agriculture, Forest Service. vi + 60 p.