1. AnASAH, M. A. H. (1933). Bull. ophthal. Soc. Egypt (Session 30, 1933), 26, 150.
2. AXENFELD, T. (1891). v. Graefes Arch. Ophthal., 37, Pt. 4, p. 102.
3. BURKI, E. (1943). Ophthalmologica (Basel), 105, 253.
4. COATS, G. (1915). Arch. Ophthal. (N. Y.), 44, 221, 235.
5. CRoci, L. (1934). Lettura Oftal., 11, 3.