Author(s):
1. Miloš Madić, Serbia
2. Miroslav Radovanović, Faculty of Mechanical Engineering in Niš, Serbia
3. Dušan Petković, Faculty of Mechanical Engineering in Niš, Serbia
4. Predrag Janković, Faculty of Mechanical Engineering in Niš, Serbia
5. Miloš Milošević, Faculty of Mechanical Engineering in Niš, Serbia