1. Corneal blindness: a global perspective;Whitcher;Bull World Health Organ,2001
2. An epidemiological study of 432 cases of penetrating keratoplasty;Xie;Yan Ke Yan Jiu,1997
3. Epidemiological study of 182 cases of keratoplasty;Yang;Zhongguo Shi Yong Yan Ke Za Zhi,2000
4. Survival analysis and visual outcome in a large series of corneal transplants in India;Dandona;Br J Ophthalmol,1997
5. The Eye Bank Association of America;Goren;Compr Ophthalmol Update,2006