1. World Health Organization, International Classification of Diseases 10th Revision, Accessed on Jan. 20, 2015 (2010)
2. Cancer Research UK. Oral cancer incidence statistics, http://www.cancerresearchuk.org/cancer-info/ cancerstats/types/oral/incidence/uk-oral-cancer- incidence-statistics , Accessed on Jan. 20, 2015 (2012)
3. K.R. Coelho, J. Cancer Epidemiol. 2012, 701932 (2012)
4. R. Sankaranarayanan, K. Ramadas, G. Thomas, Lancet 365, 1927 (2005)
5. Z.U. Khan, Webmed Central Cancer 3, WMC003626 (2012)