1. AXENFELD, T. (1904). Klin. Mbl. Augenheilk., 42 (1), 576.
2. Text-book of Ophthalmology;BARRADA, M.A.; MOHAMED, I.H.;Bull. ophthal. Soc. Egypt,1935
3. ELSCHNIG, A. (1893). Klin. Mbl. Augenheilk., 31, 191.
4. EL-SEESY, A. M. (1937). Bull. ophthal. Soc. Egypt, 30, 120.
5. A Text-book of Surgical Pathology;ILLINGWORTH, C.F.W.; DICK, B.M.,1945