Author(s):
1. Boban Andjelković, Faculty of Mechanical Engineering in Niš, Serbia
2. Dragan Milčić, Faculty of Mechanical Engineering in Niš, Serbia
3. Biljana Djordjevic, Masinski fakultet, Serbia
4. Miodrag Milčić, Faculty of Mechanical Engineering in Niš, Serbia
5. Nataša Jovanović, Faculty of Mechanical Engineering in Niš, Serbia