1. European Commission Joint Research Centre (JRC), Ispra, Italy; Department of Economics, Management and Quantitative Methods (DEMM), Università degli Studi di Milano, Milan, Italy; Institute for the Study of Labor (IZA), Bonn, Germany; and Centro Studi Luca d’Agliano (LdA), Milan, Italy.
2. Department of Computer, Control and Management Engineering (DIAG) Antonio Ruberti, Università degli Studi di Roma ‘La Sapienza’, Rome, Italy.