Pembrolizumab versus methotrexate, docetaxel, or cetuximab for recurrent or metastatic head-and-neck squamous cell carcinoma (KEYNOTE-040): a randomised, open-label, phase 3 studyEzra E.W. Cohen, Signe Friesland, Kelvin Chan et al.|The Lancet|2018Cited by 1.7k