1. Department of Economics, University of Zilina, Univerzitna 1, 010 26 Zilina, Slovakia
2. Department of Industrial Engineering, University of Zilina, Univerzitna 1, 010 26 Zilina, Slovakia
3. Department of Marketing, Trade and World Forestry, Technical University of Zvolen, T. G. Masaryka 24, 960 53 Zvolen, Slovakia