2 IZA Discussion Papers
IZA Discussion Paper No. 3389
published as "Entrepreneurial Innovation and Economic Growth" in: Journal of Macroeconomics, 2009, 31 (4), 602-613
IZA Discussion Paper No. 2558
published in: Wei-Bin Zhang (ed.), UNESCO Encyclopedia of Life Support Systems (Mathematical Models in Economics), Eolss Publishers, Oxford, UK: 2007