Author(s):
1. Jelena Najdanović, University of Niš Faculty of Medicine, Serbia
2. Vladimir Cvetković, University of Nis, Faculty of Sciences and Mathematics, ::Visegradska 33, Serbia
3. Sanja Stojanović, Faculty of Medicine, University of Niš, Niš, Serbia, Serbia
4. Milena Radenković, University of Niš Faculty of Medicine, Serbia
5. Jelena Živković, Serbia
6. Stevo Najman, Faculty of Medicine, University of Niš, Serbia