1. Department of Pulmonary Diseases, Medical Faculty, Medical University-Sofia, MHATPD “Sveta Sofia, ” 19, “Acad. Ivan Geshov” Blvd, Bulgaria
2. Department of Nephrology and Hemodialysis “Prof. I. Mitеv, ” Medical Faculty, Medical University-Sofia, 11, “Acad. Ivan Geshov” Blvd, Bulgaria