1. A Textbook of Pathology;BOYD, W.,1961
2. CROMBIE, A. L. (1967). Brit. J. Ophthal., 51, 101.
3. Text-book of Ophthalmology;DUKE-ELDER, S.,1952
4. HAYE, C., and HAUr, J. (1966). Arch. Ophtal. (Paris), 26, 183. McGAVIC, J. S. (1955). A.M.A. Arch. Ophthal., 53, 236.
5. MORTADA, A. (1964). Amer. J. Ophthal., 57, 820.