[1] Pooled mean group estimation of dynamic heterogeneous panels.Journal of the American Statistical Association， June 01, 1999 | Pesaran, M. Hashem; Shin, Yongcheol; Smith, Ron P.
[2]  Estimating long-run relationships from dynamic heterogeneous panels  M Hashem Pesaran ( mhp1@cam.ac.uk) and Ronald Smith ( r.smith@bbk.ac.uk)
Journal of Econometrics, 1995, vol. 68, issue 1, pages 79-113