Kurtul, N., H. Aksoy, S. Pençe, E. Bakan, and O. Baykal. “The Alterations of Serum Nitric Oxide Levels in Diabetic Retinopathy”. European Journal of Therapeutics, vol. 12, no. 1, Jan. 2001, pp. 22-27, doi:10.58600/eurjther.2001-12-1-1422-arch.