[1] Univ Pavia, Dept Econ, Via San Felice 5, I-27100 Pavia, Italy
[2] Politecn Milan, Dept Management Econ & Ind Engn, Via Lambruschini 4-B, I-20156 Milan, Italy
[3] Univ Milan, Dept Environm Sci & Policy, Via Celoria 2, I-20133 Milan, Italy
[4] Nederlandsche Bank, Spaklerweg 4, NL-1096 BA Amsterdam, Netherlands
[5] Univ Pavia, Pavia, Italy
[6] Nederelandsche Bank, Amsterdam, Netherlands