几篇英文文献，望大家帮忙！

 Pedroni, P, 1999,Critical Values for Cointegration Tests in Heterogeneous Panels with Multiple
Regressors[J], Oxford Bulletin of Economics and Statistics, 61: 653~670·
 Kao, C, 1999,Spurious Regression and Residual-based Tests for Cointegration in Panel Data[J],
Journal of Econometrics, 90: 1~44·
 Kao, C·and Chiang, M·H·, 2000,On the Estimation and Inference of a Cointegrated Regression
in Panel Data[J], Advances in Econometrics, 15, 179~222·