1. M.W. Morgan: Optics of Ophthalmic Optics (Professional Press, Chicago, IL 1978) pp. 1–60
2. R. Drew: Professional Ophthalmic Dispensing (Professional Press, Chicago, IL 1970) pp. 3–14
3. A.C. Guyton: Textbook of Medical Physiology, 5th edn. (W.B. Saunders, Philadelphia, PA 1976) pp. 784–792
4. E. Hecht, A. Zajac: Optics (Addison-Wesley, Reading, MA 1976) pp. 99–147
5. J.S. Stroud: “The strengthening of some commercial ophthalmic and filter glasses by ion exchange”, Glass Techn. 29, 108–114 (1988)