Khan, Rashid Ali, and Nasru Minallah. “An Improved Blood Vessel Extraction Approach from Retinal Fundus Images Using Digital Image Processing: Blood Vessel Extraction Rom Retinal Fundus Images”. Proceedings of the Pakistan Academy of Sciences: A. Physical and Computational Sciences 54, no. 2 (April 29, 2021). Accessed April 3, 2025. http://ppaspk.org/index.php/PPAS-A/article/view/242.