Ысмагул, Р. ., and А. . Нургельдина. “METHODS FOR SOLVING FREDHOLM INTEGRAL EQUATIONS”. Bulletin of Abai KazNPU. Series of Physical and Mathematical Sciences, vol. 69, no. 1, June 2021, pp. 174-8, https://bulletin-phmath.kaznpu.kz/index.php/ped/article/view/242.