1. University of Belgrade, School of Dental Medicine, Clinic for Oral Surgery, Belgrade, Serbia
2. University of Belgrade, School of Dental Medicine, Department of Medical Statistics and Informatics, Belgrade, Serbia
3. University Business Academy in Novi Sad, Faculty of Dentistry, Clinic for Oral Surgery and Implantology, Pančevo, Serbia
4. University of Belgrade, Faculty of Medicine, Department of Pathology, Belgrade, Serbia