1. World Health Organization, Fact Sheet, May 2017.
2. U.S. Department of Health Education and Welfare. Smoking and health: report of the Advisory Committee to the Surgeon General of the Public Health Service. Washington, D.C.: U.S. Department of Health, Education and Welfare, Public Health Service; 1964.
3. U.S. Department of Health and Human Services. The health consequences of smoking: 50 years of progress. A report of the Surgeon General. Atlanta, GA: U.S. Department of Health and Human Services. Office on Smoking and Health, 2014.
4. Winn DM. Tobacco use and oral disease. J Dent Educ. 2001;65(4):306–12.
5. Carranza F, Newman M, Takei H, Klokkevold, P. Carranza's Clinical Periodontology. 11th ed. St. Louis, Mo.: Elsevier Saunders; 2012. pp. 294–301.