1. Clinical Centre of Nis, Nis, Serbia
2. Faculty of Occupational Safety, University of Nis, Nis, Serbia
3. Faculty of Occupational Safety, Full member of Engineering Academy of Serbia, University of Nis, Nis, Serbia
4. Faculty of Medicine, Full member of Serbian Academy of Science and Arts, University of Nis, Nis, Serbia
5. Clinical Centre Nis, Nis, Serbia; Faculty of Medicine, University of Nis, Nis, Serbia