1. Faculty of Economics and Management, University of Szczecin, Mickiewicza 64, 71-101 Szczecin, Poland
2. Faculty of Economics, West Pomeranian University of Technology, Janickiego 31, 71-270 Szczecin, Poland
3. Institute of Economics and Finance, The John Paul II Catholic University of Lublin, Aleje Racławickie 14, 20-950 Lublin, Poland