Author(s):
1. Predrag Živković, Faculty of Mechanical Engineering in Niš, Serbia
2. Gradimir Ilić, Faculty of Mechanical Engineering in Niš, Serbia
3. Mladen Tomić, The School of Higher Technical Professional Education, Niš, Serbia
4. Mirko Dobrnjac, Faculty of Mechanical Engineering, Republic of Srpska, Bosnia and Herzegovina
5. Sadoon Ayed, Faculty of Mechanical Engineering in Niš, Serbia