1 Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124 Pisa, Italy.
2 Department of Economics, Engineering, Society and Business Organization - DEIM, Tuscia University, Via Santa Maria in Gradi, 4, 01100 Viterbo, VT Italy.
3 Department of Agricultural Economics and Policy, University of Naples "Federico II", Corso Umberto I, 40, 80138 Napoli, NA Italy.
4 Department of Agricultural Economics, Ghent University, St. Pietersnieuwstraat 33, 9000 Gent, Belgium.
5 Agricultural Economics and Rural Policy Group, Wageningen University, 6706 KN Wageningen, The Netherlands.