1. Department of Economics and Business, Faculty of Economic Sciences, University of Oradea, 1 University Street, 410087 Oradea, Romania
2. Department of Energy Engineering, Faculty of Energy Engineering and Industrial Management, University of Oradea, 410058 Oradea, Romania
3. Department of Power Engineering, Faculty of Electrical and Power Engineering, Politehnica University Timisoara, 300223 Timisoara, Romania