Dutton, Susan J, Ferry, David R, Blazeby, Jane M, Abbas, Haider, Dahle-Smith, Asa, Mansoor, Wasat, Thompson, Joyce, Harrison, Mark, Chatterjee, Anirban et al (2014) Gefitinib for oesophageal cancer progressing after chemotherapy (COG): a phase 3, multicentre, double-blind, placebo-controlled randomised trial. The Lancet Oncology, 15 (8). pp. 894-904. ISSN 1470-2045