- Kobayashi, F., T. Koizumi, Y. Akita, K. Fukuyama, A. Yamane, and T. Ikeda. 1984. Estimation of field population of Ips typographus japonicus using pheromone trap. Abstract. International Congress of Entomology, Proceedings, Hamburg 1984, 17:588.
- Koizumi, C., H. Yamaguchi, and Y. Akita. 1971. Tree mortality and infestation of the larch eightspined engraver, Ips cembrae Heer, in larch plantations in eastern Hokkaido [In Japanese, English symmary] . Hokkaido Forest Experiment Station, Annual Report 1970:140-146.
- Yoshida, N., Y. Akita, C. Koizumi, and K. Fukuyama. 1986. Field test of pheromone trap for Ips typographus in the windthrown forest caused by a typhoon . Annual Report, Hokkaido Branch, Forestry and Forest Products Research Institute (Sapporo) 1985:54-55.