Funded by the National Science Foundation PEET program (Partnerships for Enhancing Expertise in Taxonomy)
Kangas, E. 1949c. Xylechinus pilosus Ratzb. und Polygraphuspoligraphus L. (Col. Scolytidae) an der Kiefer. Annales Entomologici Fennici 15(4):168-174 (1950?).