1. Comparison of carcinogenicity of betel quid with and without tobacco;Gupta;Ecology of Disease,1982
2. Integrated biology and molecular pathology of oral cancer;Saranath,2000
3. Cancer incidence, mortality and prevalence worldwide, Version 1.0. IARC Cancer Base No.5;Fearlay,2001
4. Human papillomavirus (HPV) in head and neck cancer;Paz;Cancer,1997
5. Risk factors and risk markers for oral cancer in high incidence areas of the world;Daftary,1991