1. ARRUGA, H. (1958) Bull. Soc. franc. Ophtal., 71, 571
2. BAILLIART, j. P., and AVRILLON, J. (1964) Ibid., 77, 615
3. Brit;CROCK, G.W.; GALBRAITH, J.E.K.;J. Ophthal,1966
4. Ber. dtsch;CUSTODIS, E.;ophthal. Ges; Klin,1952
5. System of Ophthalmology;DUKE-ELDER, S.; WYBAR, K.,1961