3 IZA Discussion Papers
IZA Discussion Paper No. 9468
published in: Journal of Economic Inequality, 2015, 13 (4), 497-526.
IZA Discussion Paper No. 3809
revised version published as 'Proxying for Unobservable Variables with Internet Document-Frequency' in: Journal of the European Economic Association, 2013, 11 (1), 137–165
IZA Discussion Paper No. 1263
revised version published in: A. Heshmati (ed.), Global Trends in Income Inequality, Hauppauge, New York: Nova Science Publishers, 2007