1. Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Ivana Luičića 5, 10000 Zagreb, Croatia.
2. Department of Mathematics, J.J. Strossmayer University of Osijek, Trg Lj. Gaja 6, 31000 Osijek, Croatia.
3. Department of Physics, J.J. Strossmayer University of Osijek, Trg Lj. Gaja 6, 31000 Osijek, Croatia.