Paolo Bertoletti University of Milan-Bicocca   Department of Economics, Management and Statistics Piazza dell'Ateneo Nuovo, 1 Milan, 20126 Italy   paolo.bertoletti@unimib.it   https://sites.google.com/unipv.it/paolobertoletti/home           JEL Areas: D1 : Household Behavior: General D4 : Market Structure and Pricing: General