1. Faculty of Medical Sciences, Goce Delčev University of Štip , Štip 2000 , North Macedonia
2. Medical Faculty in Skopje, Ss. Cyril and Methodius University in Skopje , Skopje 1000 , North Macedonia
3. University Clinic for Digestive Surgery , Skopje 1000 , North Macedonia
4. Institute of Pathology, Medical Faculty in Skopje , Skopje 1000 , North Macedonia
5. Department of Visceral Surgery , University Surgery Hospital “St. Naum Ohridski”, Bul. 11 Oktomvri 53, 1000 Skopje, North Macedonia