1. Ministry of Health http://www.health.govt.nz/publication/new-cancer-registrations-2014
2. Oesophageal cancer;Smyth;Nat. Rev. Dis. Primers,2017
3. Has recognition of the relationship between mortality rates and hospital volume for major cancer surgery in California made a difference?: a follow-up analysis of another decade;Gasper;Ann. Surg.,2009
4. http://www.health.govt.nz/system/files/documents/pages/standards-of-service-provision-uppergastrointestinal-cancer-patients-dec13.doc&rct=j&frm=1&q=&esrc=s&sa=U&ei=2fd8VJ7ROuOhmQW3-YEY&ved=0CBoQFjAA&usg=AFQjCNHkOpgrh9nib9TRBvO5_SwD4Xd9Qw
5. Hospital volume and surgical mortality in the United States;Birkmeyer;N. Engl. J. Med.,2002