References
- U.S. Department of Commerce, Census Bureau . 1991 . County Business Patterns–United States Washington, DC : Dept. of Commerce .
- U.S. Department of Commerce, Census Bureau . 1993 . Responsible Care . Chemical Week , July
- Occupational Safety and Health Administration . March 1991 . The Comprehensibility of Material Safety Data Sheets Final Report March , Washington, DC : USDOL/OSHA .
- Occupational Safety and Health Administration . March 1991 . The Accuracy of Material Safety Data Sheets Final Report March , Washington, DC : USDOL/OSHA .