1. BIELSCHOWSKY, A. (1937). Arch. Ophthal. (Chicago), 17, 408.
2. BURIAN, H. M. (1947). Ibid., 37, 336.
3. BURIAN, H. M. (1951). Ibid., 46, 73.
4. Worth's Squint;CHAVASSE, F.B.,1939
5. Text-book of Ophthalmology;CUPPERS, C.;Klin. Mbl. Augenheilk; Cited by Duke-Elder,1956