1. Faculty of Economics, University of Economics in Katowice, 40-287 Katowice, Poland
2. Faculty of Informatics and Communication, University of Economics in Katowice, 40-287 Katowice, Poland
3. Faculty of Spatial Economy and Regions in Transition, University of Economics in Katowice, 40-287 Katowice, Poland
4. Faculty of Economics, VSB-Technical University of Ostrava, 702 200 Ostrava, Czech Republic