1. Professor, Faculty of Occupational Safety, Dept. of Environmental Protection, Univ. of Niš, Carnojevica 10a, 18000 Niš, Serbia.
2. Professor, Faculty of Occupational Safety, Dept. of Environmental Protection, Univ. of Niš, Carnojevica 10a, 18000 Niš, Serbia (corresponding author).
3. Teaching Assistant, Faculty of Occupational Safety, Dept. of Energy Processes and Safety, Univ. of Niš, Carnojevica 10a, 18000 Niš, Serbia.
4. Teaching Assistant, Faculty of Civil Engineering and Architecture, Dept. of Architecture, Univ. of Niš, Aleksandra Medvedeva 14, 18000 Niš, Serbia.