1. Regulatory planning and review. Executive Order No. 12,866 of September 30, 1993;U.S. President;Federal Register,1993
2. 2006
3. U.S. General Accounting Office 2003
4. Office of Management and Budget http://www.whitehouse.gov/omb/assets/omb/inforeg/2002_report_to_congress.pdf 2010