Funded by the National Science Foundation PEET program (Partnerships for Enhancing Expertise in Taxonomy)
Cook, S. P., T. L. Wagner, R. O. F. J. C. Dickens, and R. N. Coulson. 1983. Examination of sex ratios and mating habits of Ips avulsus and I. calligraphus (Coleoptera: Scolytidae). Entomological Society of America, Annals 76(1):56-60.