1. ADAMANTIADIS, B. (1951). Arch. Ophtal., n.s. 11, 457. and RANGABI, 0. (1950). Bull. Soc. hellen. ophtal., 18, 403.
2. -~ (1952). Ibid., 20, 31.
3. Text-book of Ophthalmology;DUKE-ELDER, S.,1940
4. VAIL, D. (1941). Amer. J. Ophthal., 24, 403.
5. VAIL, D. (1946). Ibid., 29, 785.