Luca Spataro Dipartimento di Economia e Management, University of Pisa, Italy   via C. Ridolfi 10 Pisa, 56124 Italy   l.spataro@ec.unipi.it   http://www.dse.ec.unipi.it/persone/docenti/spataro/index.htm           JEL Areas: G1 : General Financial Markets: General (includes Measurement and Data) Q5 : Environmental Economics: General