1. University of Novi Sad, Faculty of Sciences, Trg Dositeja Obradovića 4, 21000 Novi Sad, Serbia
2. University of Novi Sad, Faculty of Technical Sciences, Trg Dositeja Obradovića 6, Novi Sad, Serbia
3. University of Belgrade, Faculty of Physics, Studentski trg 12, 11000 Belgrade, Serbia