4 IZA Discussion Papers
IZA Discussion Paper No. 15544
IZA Discussion Paper No. 7695
published in: International Journal of Innovation Management, 2016, 20(7), 235-257.
IZA Discussion Paper No. 842
published in: Journal of Public Economics, 2005, 89 (11-12), 2165-2181
IZA Discussion Paper No. 634
published in: Journal of Labor Economics, 2005, 23 (3), 437-466