1. STUDENT SCIENTIFIC CIRCLE AT THE DEPARTMENT OF ENVIRONMENTAL MEDICINE AND EPIDEMIOLOGY IN ZABRZE, FACULTY OF MEDICAL SCIENCES IN ZABRZE, SILESIAN MEDICAL UNIVERSITY IN KATOWICE, ZABRZE, POLAND
2. ST, LUKE HOSPITAL, TARNÓW, POLAND
3. CITY HOSPITAL NO. 4 IN GLIWICE, GLIWICE, POLAND
4. DEPARTMENT OF ENVIRONMENTAL MEDICINE AND EPIDEMIOLOGY IN ZABRZE, FACULTY OF MEDICAL SCIENCES IN ZABRZE, SILESIAN MEDICAL UNIVERSITY IN KATOWICE, ZABRZE, POLAND