Author(s):
1. Dane Marčeta, Faculty of Forestry, University of Banja Luka, Republic of Srpska, Bosnia and Herzegovina
2. Vladimir Petković, Faculty of Forestry, University of Banja Luka, Republic of Srpska, Bosnia and Herzegovina
3. Gordana Lakić Globočki, University of Banja Luka, Faculty of mechanical engineering, Republic of Srpska, Bosnia and Herzegovina