Утеуова, Н., К. Шияпов, А. Бекбауова, and Б. Шарипова. “SOLVING NONLINEAR BOUNDARY VALUE PROBLEMS BY THE APPROXIMATE METHOD”. Bulletin of Abai KazNPU. Series of Physical and Mathematical Sciences, vol. 84, no. 4, Dec. 2023, pp. 46-54, doi:10.51889/2959-5894.2023.84.4.005.