Funded by the National Science Foundation PEET program (Partnerships for Enhancing Expertise in Taxonomy)
Inouye, M., C. Koizumi, and M. Takai. 1954. On the hibernation of the Todo-fir bark beetles, Polygraphus proximus Blandford, Cryphalus piceae Ratzeburg and C. piceus Eggers (Ipidae). Japanese Forestry Society, Journal 36(5): 127-129.