Historical roots of political extremism : the effects of Nazi occupation of Italy / Nicola Fontana (London School of Economics), Tommaso Nannicini (IGIER, Bocconi University, CEPR and IZA), Guido Tabellini (IGIER, Bocconi University, CIFAR, CEPR, and CESIfo) ; IZA, Institute of Labor Economics. Bonn, Germany : IZA Institute of Labor Economics, February 2017