Author(s):
1. Emina Petrovic, Faculty of Mechanical Engineering in Niš, Serbia
2. Miloš Simonović, Faculty of Mechanical Engineering in Niš, Serbia
3. Nevena Tomic, Serbia
4. Vlastimir Nikolic, Faculty of Mechanical Engineering in Niš, Serbia
5. Ivan Ćirić, Faculty of Mechanical Engineering in Niš, Serbia