1. U.S. DHHS (1989) Reducing the health consequences of smoking: 25 years of progress: a report of the Surgeon General. Atlanta, GA, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health.
2. CDC (2002) www.cdc.gov/tobacco/research_data/adults_prev/adstat3.htm and www.cdc.gov/tobacco/research_data/adults_ prev/tab_3.htm, CDC website.