1. EC Directive 76/768/EC (Last Amendment 89/679/EC).
2. The Shorter Oxford English Dictionary, 3rd edn, 1980.
3. Chemist and Druggist: Oral Hygiene. July 28, 1990.
4. Jenkins, G.N. (1978) The Physiology and Biochemistry of the Mouth, 4th edn, Blackwell Scientific, Oxford.
5. Manhold, J.H. and Balbo, M.P. (1985) Illustrated Dental Terminology. Lippincott, Philadelphia.