[1] Univ Palermo, Dept Econ Business & Stat SEAS, I-90128 Palermo, Italy
[2] Univ Coimbra, Fac Econ, P-3004512 Coimbra, Portugal
[3] Univ Minho, Dept Econ, P-4710057 Braga, Portugal
[4] Univ Minho, Econ Policies Res Unit NIPE, P-4710057 Braga, Portugal
[5] OECD, Econ Dept, F-75775 Paris 16, France
[6] Univ London London Sch Econ & Polit Sci, LSE Alumni Assoc, London WC2A 2AE, England