Survival of patients with resected N2 non-small-cell lung cancer: evidence for a subclassification and implications. - Andre,F.; Grunenwald,D.; Pignon,J.P.; Dujon,A.; Pujol,J.L.; Brichon,P.Y.; Brouchet,L.; Quoix,E.; Westeel,V.; Le Chevalier,T. (J Clin Oncol, 2000)