Alberto Iozzi University of Rome Tor Vergata   Dept. Sefemeq Faculty of Economics Via di Tor Vergata Rome, I-00133 Italy   Alberto.Iozzi@UniRoma2.It   http://www.economia.uniroma2.it/sefemeq/professori/iozzi           JEL Areas: L0 : Industrial Organization: General H0 : Public Economics: General