1. Parasitology;Chatterjee, K.D.,1971
2. Duke-Elder, S. (1965). System of Ophthalmology, Vol. 8, p. 401. Kimpton: London.
3. Sr stem of;Duke-Elder, S.;Ophthalmology,1966
4. Jones, T., Jordan, L. W., and Sullivan, N. P. (1938). Archives of Ophthalmology, 20, 1006.
5. Mercier (1771) quoted in Parsons, J. H. (1904). Pathology of the Eye, Vol. 1, p. 321.