1. Department of Economics , Kozminski University , Jagiellońska Street, 57/59 – 03301 Warsaw , Poland
2. Department of Economics and Management , University of Pisa , Via Cosimo Ridolfi, 10, I-56124 Pisa , PI , Italy
3. Department of Law , University of Pisa , Via Collegio Ricci, 10, I-56126 Pisa , PI , Italy