1. Bagella , M. Becchett , I. L. Hasan , I. 2000 The negative impact on growth of “export portfolio volatility”: Benefits of economic integration and lessons for the Latinamerican case http://www.bcv.org.ve/viencuentro/bagellabecchetti.pdf
2. Economic growth in a cross section of countries;Barro;Quarterly Journal of Economics,1991
3. Convergence;Barro;Journal of Political Economy,1992