1. EuroDerma Clinic Sofia Bulgaria
2. Department of Dermatology and Venerеology Acibadem City Clinic Tokuda University Hospital Sofia Bulgaria
3. Department of Dermatovenereology and Allergology Medical University Pleven Pleven Bulgaria
4. Department of Dermatology and Venereology Trakia University Stara Zagora Bulgaria
5. Department of Dermatology and Venereology, Medical Faculty Medical University of Sofia Sofia Bulgaria