Author(s):
1. Stefan Djordjevic, University of Niš, Faculty of Sciences and Mathematics, Department of Physics, Višegradska 33, 1800, Serbia
2. Lana Pantic, University of Niš, Faculty of Sciences and Mathematics, Department of Physics, Višegradska 33, 1800, Serbia
3. Marko Krstic, University of Niš, Faculty of Sciences and Mathematics, Department of Physics, Višegradska 33, 1800, Serbia
4. Ivana Radonjić Mitić, University of Niš, Faculty of Sciences and Mathematics, Department of Physics, Višegradska 33, Niš, Serbia
5. Tomislav Pavlović, University of Nis, Faculty of Sciences and Mathematics, , Serbia
6. Dragoljub Mirjanić, Akademija nauka i umjetnosti Republike Srpske, Republic of Srpska, Bosnia and Herzegovina
7. Andjelina Maric Stankovic, University of Niš, Faculty of Sciences and Mathematics, Department of Physics, Višegradska 33, 1800, Serbia

Abstract