Author(s):
1. Rada Petrovic, Faculty of Technology Banja Luka, Republic of Srpska, Bosnia and Herzegovina
2. Jelena Penavin-Škundrić, Prirodno-matematički fakultet Banja Luka, Republic of Srpska, Bosnia and Herzegovina
3. Branko Škundrić, Akademija nauka i umjetnosti Republike Srpske, Republic of Srpska, Bosnia and Herzegovina
4. Nedeljko Cegar, Faculty of Technology Banja Luka, Republic of Srpska, Bosnia and Herzegovina

Abstract