Abstract
The authors thank Alberto Bucci, Massimo Florio, Gareth Myles and two anonymous referees for helpful comments and suggestions, Eleonora Colombo for providing excellent research assistance and Judith Payne for excellent editorial assistance. An earlier version of this paper was presented at the VIII Milan European Economy Workshop, 11–12 June 2009, University of Milan, in the framework of the EIBURS project, sponsored by the European Investment Bank (EIB). The authors gratefully acknowledge the EIBURS financial support. The usual disclaimer applies and the views of the authors do not necessarily reflect those of the EIB.
