- Yasunaga, K. 1962a. Studies on attractants for the pine bark beetles, II Field tests on the attractability of benzoic acid [In Japanese]. Japanese Forestry Society, Journal 44197-200.
- Yasunaga, K. 1962b. Studies on the natural enemies of the beetles injurious to pine trees in Kyushu [In Japanese] . Kontyu 30:41-49.
- Yasunaga, K. 1964. A guide for identification of the pine bark beetles and their natural enemies [In Japanese]. Kumanoto. 123 p.
- Yasunaga, K., Y. Oshima, and S. Kuwatsuka. 1962. Studies on the attractants of the pine bark beetles, I. Isolation of an attractant, benzoic acid [In Japanese]. Agricultural Chemical Society of Japan, Journal 36:802-804.
- Yasunaga, K., Y. Oshima, and Y. Kuwatsuka. 1963. Studies on attractants of the pine bark beetles, III. Screening tests of attractancy and synergism of benzoic acid derivatives, higher fatty acids and their esters and terpineols [In Japanese]. Agricultural Chemical Society of Japan, Journal 37:642-644.