3 IZA Discussion Papers
IZA Discussion Paper No. 6612
IZA Discussion Paper No. 2599
published in: Applied Economics Letters, 2009, 16 (9), 877-883
IZA Discussion Paper No. 1497
published in: Scottish Journal of Political Economy, 2007, 54 (5), 661-683 (Special Issue on Labour Contracts and Wages over the Cycle)