1. Department of Management, Economics and Quantitative Methods, University of Bergamo, Via dei Caniana, 2, 24127 Bergamo, Italy
2. Department of Finance, VŠB-TU Ostrava, Sokolská třída 33, Ostrava 701 21, Czech Republic
3. Department of Economics and Management, University of Trento, via Inama 5, I-38122 Trento, Italy