4Barro, R., and Sala-i-Martin, X., 1992, "Convergence" [J], Journal of Political Economy, Vol.100, pp. 223-251.
5Bai, J. and Ng, S., 2002, "Determining the Number of Factors in Approximate Factor Models" [J], Econometrica, Vol.70, pp. 191-221.
6Bai, J. and Ng, S., 2004, "A PANIC Attack on Unit Roots & Cointegration" [J], Econometrica, Vol.72, No.4, pp.1127-1177.
7Bai, J. and Ng, S., 2010, "Panel Unit Root Tests with Cross-Section Dependence: A Further Investigation" [J], Econometric Theory, Vol.26, pp. 1088-1114.
8Carlino, G. A. and Mills, L. O.,1993," Are US Regional Incomes Converging? A Time Series Analysis" [J], Journal of Monetary Economics,Vol.32, pp.335-346.
9Evans, P and Karras, G., 1996, "Convergence Revisited" [J], Journal of Monetary Economics, Vol.37, No.2, pp. 249-265.
10Evans,P.,1998, "Using Panel Data to Evaluate Growth Theories" [J], International Economic Reviews, Vol.39, No.2, pp.295-306.