- Voolma, K., H. Ounap, and I. Suda. 1997b. Eesti urasklaste (Coleoptera, Scolytidae) maaraja [Estonian bark beetles (Coleoptera, Scolytidae) Eesti Pollumajandusulikool Metsandusteaduskond, Tartu., 43 pp. pp..
- Voolma, K., H. Ounap, and I. Suda. 1997a. Bark beetles (Coleoptera: Scolytidae) of Estonia: Results of the examination of insect collections. Baltic Forestry 319-23.
- Voolma, K., H. Ounap, and I. Suda. 2000. Eesti putukate levikuaslas, kd 2, kaardid 98-165: Urasklased (Scolytidae) [Distribution maps of Estonian insects, vol 2, maps 98-165: Scolytidae]. Eesti Looduseuurijate Selts, Tartu.
- Voolma, K., H. Ounap, and I. Suda. 1996. Uraslased (Coleoptera, Scolytidae) eesti entomoloogilistes kollektsioonides [Bark beetles (Coleoptera, Scolytidae) in the insect collections of Estonia]. Metsanduslikud Uurimused 27125-132.
- Mihkelson, S., and H. Ounap. 1983. Feromoonide mojust kuuse-kooreuraski Ips typographus L. [Effect of pheromones on the aggregation of Ips typographus]. Metsanduslikud Uurimused. Estonian SSR 18, 154-160 p.
- Ounap, H. 1992. Laboratory studies of the food selection of some predators of bark beetles (Coleoptera: Scolytidae) . Eesti Teaduste Akadeemia Toimetised, Bioloogia 41:131-140.
- Öunap, H. 1992a. On the species composition of the predatory Diptera established in the boreholes of bark beetles inhabiting conifers in Estonia [In Russian]. Metsanduslikud Uurimused 24:143-151.
- Öunap, H. 1992b. Urasklaste entomofaagide uurimisest eestis. [Investigations into entomophagous insects feeding on bark beetles in Estonia]. Pages 66-73 In Eesti Metsade Kaitse ja Kasutamine, Eesti Teaduste Akadeemia Looduskaitse Komisjon, Tallinn.
- Öunap, H. 1996. Saareuraskitest (Hylesinus) ja kaabusuraskitest (Crypturgus) (Coleoptera, Scolytidae) eestis [Hylesinus and Crypturgus (Coleoptera, Scolytidae) in Estonia]. Metsanduslikud Uurimused 27:133-139.
- Öunap, H. 1997. Two new species of the genus Medetera (Diptera, Dolichopodidae) from Estonia and Sweden . Proceedings of the Estonian Academy of Sciences, Biology, Ecology 46:123-128.
- Öunap, H. 1999. Medetera-flies (Diptera, Dolichopodidae) as enemies of bark beetles (Coleoptera, Scolytidae) in Estonia. Pages 133-144 In K.J. Elberg, (ed.), Proceedings of the XXIV Nordic Congress of Entomology, August 8-11, 1997, Tatru, Estonia. University of Tartu, Tartu, Estonia.
- Voolma, K., and H. Õunap. 1994. Additions to the list of bark beetles (Coleoptera, Scolytidae) in Estonia . Metsanduslikud Uurimused 26:110-112.
- Voolma, K., I. Süda, and H. Õunap. 1998. New records of bark beetles (Coleoptera, Scolytidae) from Estonia . Proceedings of the Estonian Academy of Sciences, Biology, Ecology 47:73-78.