1. Department of MEQM, University of Bergamo, Via dei Caniana 2, Bergamo, 24127, Italy
2. Department of MEQM, University of Bergamo, Via dei Caniana 2, Bergamo, 24127, Italy and Department of Finance, VŠB Technical University of Ostrava, Faculty of Economics, Sokolská třída 33, 702 00, Ostrava, Czech Republic