Validation of the 8th edition UICC/AJCC TNM staging system for HPV associated oropharyngeal cancer patients managed with contemporary chemo-radiotherapy oleh Kirsten van Gysen, Mark Stevens, Linxin Guo, Dasantha Jayamanne, David Veivers, Andrew Wignall, Leo Pang, Alexander Guminski, Adrian Lee, George Hruby, Paula Macleod, Alon Taylor, Thomas Eade