Ashyralyev, A., and M. Urun. “On the Crank-Nicolson Difference Scheme for the Time-Dependent Source Identification Problem”. Bulletin of the Karaganda University. Mathematics Series 102, no. 2 (June 30, 2021): 35–44. Accessed December 8, 2025. https://mts.buketov.edu.kz/mathematics-vestnik/article/view/410.