1. Department of Agricultural and Forest Sciences (DAFNE), University of Tuscia, Viterbo, Italy
2. Department of Mathematics, Computer Science and Economics, University of Basilicata, Potenza, Italy
3. Department of Economics and Law, University of Macerata, Via Armaroli 43, I-62100 Macerata, Italy
4. Global Change Research Institute of the Czech Academy of Sciences, České Budějovice, Czech Republic