1. PhD, VŠB – Technical University of Ostrava, Faculty of Economics, Sokolská třída 33, 702 00 Ostrava, Czech Republic.
2. Ing. PhD, University of Presov, Faculty of Management and Business, Konštantínova 16, Prešov 080 01, Slovak Republic.
3. Associate Professor, University of Presov, Faculty of Management and Business, Konštantínova 16, Prešov 080 01, Slovak Republic.
4. Manager PhD, Institute of Earth Resources, Faculty of Mining, Ecology, Process Control and Geotechnologies, Technical University of Košice, Letná 9, Košice 042 00, Slovak Republic.