Singh, G., S. Monga, H. Bhandari, V. Aggarwal, R. Dhingra, and A. Jain. “Visual Outcome in Patients Undergoing Penetrating Keratoplasty”. International Journal of Research in Medical Sciences, vol. 3, no. 1, Jan. 2017, pp. 244-9, https://www.msjonline.org/index.php/ijrms/article/view/1243.