Funded by the National Science Foundation PEET program (Partnerships for Enhancing Expertise in Taxonomy)
Linnaniemi, W. M. A. 1916b. Pityogenes chalcographus L. ja Ips duplicates Sahlb. Kertomus tuhohyonteisten esiintymisesta Suomessa v. 1914. Helsinski, p. 20-21.