Technological Change and Employment : were Ricardo and Marx right? / Mariacristina Piva (Università Cattolica del Sacro Cuore, Piacenza), Marco Vivarelli (Università Cattolica del Sacro Cuore, Milano, UNU-MERIT and IZA) ; IZA, Institute of Labor Economics. Bonn, Germany : IZA Institute of Labor Economics, January 2017