4 IZA Discussion Papers
IZA Discussion Paper No. 17188
IZA Discussion Paper No. 16229
IZA Discussion Paper No. 8936
IZA Discussion Paper No. 2075
revised version published as 'Multiple Experiments for the Causal Link between the Quantity and Quality of Children' in: Journal of Labor Economics, 2010, 28 (4), 773 - 824