- Valkama, H., P. Martikainen, and M. Räty. 1997. First record of North American ambrosia beetle Gnathotrichus materiarius (Fitch) (Coleoptera, Scolytidae) in Finland — a new potential forest pest? . Entomologica Fennica 8:193-195.
- Valkama, H., M. Räty, and P. Niemela. 1997. Catches of Ips duplicates and other non-target Coleoptera by Ips typographus pheromone trapping . Entomologica Fennica 8:153-159.