1. Institute of Pathology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia
2. Department of Gastroenterology, Hepatology and GI Endoscopy, University Children’s Hospital, 11000 Belgrade, Serbia
3. Institute of Medical Statistics and Informatics, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia
4. Institute of Anatomy, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia
5. Department of Pathology, University Clinical Center Tuzla, 75000 Tuzla, Bosnia and Herzegovina