1. Fundamental Problems of Federal Income Taxation,;Quarterly Journal of Economics,1921
2. Designing VAT Systems: Some Efficiency Considerations,;Review of Economics and Statistics,1996
3. Tax Innovations and Public Revenues in Sub-Saharan Africa,;Journal of Development Studies,2015
4. The Collection Efficiency of the Value Added Tax: Theory and International Evidence,;Journal of International Trade & Economic Development,2008