1. The Bacteriology of the Eye;AXENFELD, T.;trans. A. Macnab,1908
2. In "Systemic Ophthalmology ";BALLANTYNE, A.J.,1951
3. BELLOWS, J. G. (1951). Ibid., p. 139.
4. DAVENPORT, R., and SMITH, C. (1952). British Journal of Ophthalmology, 36, 389.
5. Text-book of Ophthalmology;DUKE-ELDER, S.,1947