1. Department of Propaedeutics of Internal Diseases “Prof. Dr. Anton Mitov”, Faculty of Medicine, Medical University of Plovdiv, 4002 Plovdiv, Bulgaria
2. Clinic of Rheumatology, University Hospital “St. George”, 4000 Plovdiv, Bulgaria
3. Second Department of Internal Diseases, Section “Gastroenterology”, Medical Faculty, Medical University of Plovdiv, 4002 Plovdiv, Bulgaria
4. Clinic of Gastroenterology, University Hospital “Kaspela”, 4001 Plovdiv, Bulgaria
5. Department of Special Surgery, Faculty of Medicine, Medical University of Plovdiv, 4002 Plovdiv, Bulgaria
6. Second Surgery Clinic, University Hospital “St. George”, 4000 Plovdiv, Bulgaria
7. Department of Otorhinolaryngology, Medical Faculty, Medical University of Plovdiv, 4002 Plovdiv, Bulgaria
8. Department of Ophthalmology, Faculty of Medicine, Medical University of Plovdiv, University Eye Clinic, University Hospital, 4000 Plovdiv, Bulgaria
9. Department of Rheumatology, Clinic of Rheumatology, University Hospital St. Ivan Rilski, Medical Faculty, Medical University of Sofia, 1000 Sofia, Bulgaria