Faculty of Medicine, University of Belgrade, Serbia
Clinic for Allergology and Immunology, Clinical Centre of Serbia, Belgrade, Serbia
General Hospital Užice, Serbia
Institute of Medical Statistics and Informatics, Faculty of Medicine, University of Belgrade, Serbia
Institute of Social Medicine, Faculty of Medicine, University of Belgrade, Serbia
Department of Otorhinolaryngology, Faculty of Medicine, University of Priština, Kosovska Mitrovica, Serbia
Institute of Epidemiology, Faculty of Medicine, University of Belgrade,Serbia