Source:"The Health Consequences of Using Smokeless Tobacco: A Report of the Advisory Committee to the Surgeon General." U.S. Department of Health and Human Services, Public Health Service, NIH Pub. Bethesda, MD. Apr. 1986. Report.
Source:"The Health Consequences of Smoking—50 Years of Progress. Surgeon General's Report." U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health. Cancer, 2014: 9. Report.