Author(s):
1. Jelena Petrovic, Faculty of Mechanical Engineering in Niš, Serbia
2. Zivojin Stamenkovic, Faculty of Mechanical Engineering in Niš, Serbia
3. Milos Kocic, Faculty of Mechanical Engineering in Niš, Serbia
4. Milica Nikodijevic, University of Nis, Faculty of Occupational Safety, Serbia
5. Jasmina Bogdanović-Jovanović, Faculty of Mechanical Engineering in Niš, Serbia