4 IZA Discussion Papers
IZA Discussion Paper No. 7827
IZA Discussion Paper No. 5889
IZA Discussion Paper No. 5436
published in: Research in Labor Economics, 2014, 40, 293-324
IZA Discussion Paper No. 3198
published in: History & Mathematics: Processes and Models of Global Dynamics, Volgograd, Russia, 2010, 92 – 137