1. 1. Estrin, N.F., Crosley, P.A., and Haynes, C.R. (eds.). (1982). CTFA Cosmetic Ingredient Dictionary, 3rd ed. Washington, DC: The Cosmetic Toiletry and Fragrance Assoc., p. 232.
2. 2. Greenberg, L.A., and Lester, D. (1954). Handbook of Cosmetic Materials. New York: Interscience, p. 258.
3. 3. Hawley, G.G. (ed.). (1971). The Condensed Chemical Dictionary, 8th ed. New York: Van Nostrand Reinhold, p. 680.
4. 5. Sax, N.I. (ed.). (1979). Dangerous Properties of Industrial Materials, 5th ed. New York: Van Nostrand Reinhold, p. 902.
5. 7. Windholz, M. (ed.). (1976). The Merk Index, 9th ed. Rahway, NJ: Merck & Co., p. 948.