1. Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11129 Belgrade, Serbia
2. Clinic for Otorhinolaryngology and Maxillofacial Surgery, University Clinical Center of Serbia, Pasterova 2, 11000 Belgrade, Serbia
3. Hospital for ENT, KBC “Dragiša Mišović”, 11000 Belgrade, Serbia
4. Clinical Centre of Montenegro, Centre for Abdominal Surgery, 81000 Podgorica, Montenegro
5. Clinical Centre of Serbia, Clinic for Psychiatry, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia