1. Department of Internal Medicine; Faculty of Medical Sciences, University of Kragujevac; Kragujevac Serbia
2. Faculty of Medicine; Institute of Medical Statistics and Informatics, University of Belgrade; Belgrade Serbia
3. Faculty of Medicine; University of Pristina, Kosovska Mitrovica; Serbia
4. Faculty of Dentistry; University of Pristina, Kosovska Mitrovica; Serbia
5. Clinical Center Nis; Nis Serbia
6. Clinical Hospital Center Pristina; Gracanica Serbia