1. U.S. Food and Drug Administration Everything Added to Food in the United States (EAFUS) http://www.accessdata.fda.gov/scripts/fcn/fcnNavigation.cfm?rpt=eafus
2. Code of Federal Regulations Title 21 Food and Drugs Volume 3 Definitions http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm
3. Navigating the U.S. Food Additive Regulatory Program
4. Food Colorants