Authors
A. Keltchev
Department of Cardiac Surgery, University Hospital “Acibadem City Clinic” – Sofia, Bulgaria
S. Kazakov
Department of Cardiac Surgery, University Hospital “Acibadem City Clinic” – Sofia, Bulgaria
M. Alexieva
Department of Respiratory Diseases, Medical University – Sofia, Bulgaria
E. Mekov
Department of Occupational Diseases, Medical University – Sofia, Bulgaria
G. Yankov
Department of Respiratory Diseases, Medical University – Sofia, Bulgaria
