Author(s):
1. Sanja Stojanović, University of Niš Faculty of Medicine, Serbia
2. Jelena Najdanović, University of Niš Faculty of Medicine, Serbia
3. Žarko Mitić, University of Niš Faculty of Medicine, Serbia
4. Perica Vasiljević, University of Nis, Faculty of Sciences and Mathematics, ::Visegradska 33, Serbia
5. Nenad Ignjatović, Institute of Technical Sciences of the Serbian Academy of Sciences and Arts, Belgrade, Serbia, Serbia
6. Stevo Najman, Faculty of Medicine, University of Niš, Serbia