Author(s):
1. Dragan Cvetković, Fakultet inženjerskih nauka Univerziteta u Kragujevcu, Serbia
2. Aleksandar Nešović, Faculty of Engineering, University of Kragujevac, Sestre Janjić 6, 34000 Kragujevac, Srbija 2IMW Ins, Serbia
3. Ljubiša Bojić, Faculty of Engineering, University of Kragujevac, Sestre Janjić 6, 34000 Kragujevac, Srbija 2IMW Ins, Serbia