Kipli, Kuryati, et al. “Morphological and Otsu’s Thresholding-Based Retinal Blood Vessel Segmentation for Detection of Retinopathy”. International Journal of Engineering & Technology, vol. 7, no. 3.18, Aug. 2018, pp. 16-20, https://doi.org/10.14419/ijet.v7i3.18.16665.