1. Harwood HJ . Economic Costs of Alcohol Abuse in the United States: Estimates, Update Methods, and Data. Rockville, MD: National Institute on Alcohol Abuse and Alcoholism; 2000. NIH Publication No. 98–4327.
2. Substance Abuse and Mental Health Services Administration. Substance Use and Mental Health Characteristics by Employment Status. Office of Applied Studies, US Department of Health and Human Services Rockville, MD; 1999.
3. Backer TE . Strategic Planning for Workplace Drug Abuse Programs. National Institute on Drug Abuse Office of Research Communications, Pub. No. ADM 87-1538. Washington, DC: US Government Printing Office; 1987.
4. US Department of Labor. What Works: Workplaces Without Drugs. Washington, DC: US Department of Labor; 1991.
5. DeNavas-Walt C, Proctor B, Mills R . Income, Poverty, and Health Insurance Coverage in the United States: 2003. Washington, DC: US Census Bureau, US Government Printing Office; 2004. Current Population Reports, p. 60–226.