[1] Juraj Dobrila Univ Pula, Fac Econ & Tourism Dr Mijo Mirkovic, Zagrebacka 30, Pula 52100, Croatia
[2] Univ Econ & Human Sci Warsaw, Okopowa 59, PL-01043 Warsaw, Poland
[3] Tomas Bata Univ Zlin, Fac Management & Econ, Mostni 5139, Zlin 76001, Czech Republic
[4] Tech Univ Kosice, Fac Min Ecol Proc Control & Geotechnol, Letna 9, Kosice 04200, Slovakia