Shah, Zaman, et al. “Treatment of Advance Keratoconus Using Donor Bowman Layer: The Zaman Technique of Bowman Layer Transplantation (Type I & Type II)”. International Journal of Clinical and Experimental Ophthalmology, vol. 6, no. 1, May 2022, pp. 015-2, doi:10.29328/journal.ijceo.1001045.