First Author:   Claudio Detotto Dipartimento Economia, Impresa e Regolamentazione (DEIR) and CRENoS, University of Sassari cdetotto@uniss.it   via torre tonda 34 sassari, 07100, italy       http://sites.google.com/site/claudiodetotto/ Second Author: Pulina Manuela School of Economics and Management, Fac. of Economics, Free Univ. Bolzano; CRENoS, Univ. Sassari mpulina@uniss.it   sassari, 07100, italy