1. in Developments in Food Colours, vol. 2. Ed., Elsevier, New York, 1984, p. 4.
2. Handbook of U.S. Colorants for Foods, Drugs, and Cosmetics, Wiley, New York, 1979
3. The Analytical Chemistry of Synthetic Dyes, Wiley, New York, 1977.
4. Separation and Identification of Food Colours Permitted by the Colouring Matter in Food Regulations, Association of Public Analysts, London, 1960