Berikkhanova Г.Е., Zholymbayev О.М., and A. Aniyarov. “SOME PHYSICAL PROBLEMS THAT LEAD TO THE BESSEL EQUATION”. Bulletin of Abai KazNPU. Series of Physical and mathematical sciences 82, no. 2 (June 27, 2023): 90–99. Accessed April 13, 2025. https://bulletin-phmath.kaznpu.kz/index.php/ped/article/view/748.