Author(s):
1. Jelena Trivan, Rudarski institut Prijedor, e-mail Save Kovačevića bb, Prijedor,
Republic of Srpska, Bosnia and Herzegovina
2. Irena Rajlić, ArcelorMittal Prijedor,
Republic of Srpska, Bosnia and Herzegovina
3. Ljubica Figun, Rudarski fakultet Prijedor,
Republic of Srpska, Bosnia and Herzegovina