Author(s):
1. Jelena Penavin-Škundrić, Prirodno-matematički fakultet Banja Luka, Republic of Srpska, Bosnia and Herzegovina
2. Zorica Levi, Faculty of Technology Banja Luka, Republic of Srpska, Bosnia and Herzegovina
3. Slavica Sladojević, 4. Rada Petrovic, Republic of Srpska, Bosnia and Herzegovina
5. Darko Bodroža, Republic of Srpska, Bosnia and Herzegovina

Abstract Final paper Paper for reviews