7Barro, Robert. J. and Sala - i - Martin, Xavier. "Convergence. "Journal of Political Economy, 1992, 100 (2), pp. 223 - 251.
8Gylfason, Thorvaldur. "Natural Resources, Education and Economic Development. "European Economic Review, 2001,45, pp. 847 - 869.
9Gylfason, Thorvaldur."Resources, Agriculture, and Economic Growth in Economics in Transition. "Kyklo, 2005, 53(4), pp. 545 -580.
10Kaufman, Daniel ; Kraay, Aart and Mastruzzi, Massimo. "Governance Matters Ⅲ: Governance Indicators for 1996 - 2002. " World Bank working paper, 2003.