Topotecan an new drug in the second-line treatment of small-cell lung cancer: A phase II study of patients with refractory and sensitive disease. - Ardizzoni,A.; Hansen,H.; Dombernowsky,P.; Gamucci,T.; Kaplan,S.; Postmus,P.; Giaccone,G.; Schaefer,B.; Wanders,J.; Verweij,J. (J Clin Oncol, 1997)