Author(s):
1. Rada Petrović, Faculty of Technology Banja Luka, Republic of Srpska, Bosnia and Herzegovina
2. Dragana Gajić, Prirodno-matematički fakultet Banja Luka, Republic of Srpska, Bosnia and Herzegovina
3. Darko Bodroža, Faculty of Technology Banja Luka, Republic of Srpska, Bosnia and Herzegovina
4. Zora Levi, Republic of Srpska, Bosnia and Herzegovina
5. Darija Kičić, Prirodno-matematički fakultet Banja Luka, Republic of Srpska, Bosnia and Herzegovina