1. Clinic for Treatment of Nonspecific Lung Diseases and Tuberculosis UMHAT “St. Ivan Rilski”, Medical University—Sofia Sofia Bulgaria
2. Department of Pathomorphology UMHAT "St. Ivan Rilski", Medical University—Sofia Sofia Bulgaria
3. Department of Professional Diseases UMHAT “St. Ivan Rilski”, Medical University—Sofia Sofia Bulgaria
4. Department of Intensive Care, Clinic for Cardiology UMHAT “Alexandrovska”, Medical University—Sofia Sofia Bulgaria