1. Institute for Child and Youth Healthcare of Vojvodina, Clinic for Pediatric Surgery, Novi Sad, Serbia + University of Novi Sad, Faculty of Medicine, Novi Sad, Serbia
2. Dr. Vukan Čupić Mother and Child Health Care Institute of Serbia, Department of Clinical Pathology, Belgrade, Serbia + Banja Luka University, Faculty of Medicine, Banja Luka, Republic of Srpska, Bosnia and Herzegovina