Ahmad, S. S., C. Binson, C. K. Lung, and . S. A. Ghani. “Bilateral Persistent Pupillary Membranes Associated With Cataract”. Digital Journal of Ophthalmology, vol. 17, no. 4, Nov. 2011, pp. 62-65, doi:10.5693/djo.02.2011.10.001.