Obed, Sami, Parzhin Mohammed, and Dler Kadir. “The Estimation of (Covid-19) Cases in Kurdistan Region Using Nelson Aalen Estimator”. Cihan University-Erbil Scientific Journal 5, no. 2 (September 30, 2021): 24-31. Accessed March 29, 2024. https://journals.cihanuniversity.edu.iq/index.php/cuesj/article/view/448.