15. Xu, L., Wang, Y., Li, Y., Cui, T., Li, J., and Jonas, J. B. (2006) Causes of blindness and visual impairment in urban and rural areas in Beijing: the Beijing Eye Study. Ophthalmology 113, 1134 e1131-1111

15. Xu, L., Wang, Y., Li, Y., Cui, T., Li, J., and Jonas, J. B. (2006) Causes of blindness and visual impairment in urban and rural areas in Beijing: the Beijing Eye Study. Ophthalmology 113, 1134 e1131-1111