1. Leicester, H.M.: Biochemistry of the Teeth. St. Louis: C.V. Mosby Co., 1949, p 29.
2. Brudevold, F. "Chemical Composition of the Teeth in Relation to Caries," in SOGN-NAES, R.F., Chemistry and the Prevention of Dental Caries. Springfield, Ill.: Charles C Thomas, 1962, p 34.
3. Chemical Composition of Enamel and Dentin. II. Fluorine Content
4. Calcification. XXVI. Caries Susceptibility in Relation to Composition of Teeth and Diet
5. Jenkins, G.N.: The Physiology of the Mouth, 3rd ed, Philadelphia: Davis, 1966, pp 228-229.