Берикханова , Г., О. . Жолымбаев, and Анияров A. “SOME PHYSICAL PROBLEMS THAT LEAD TO THE BESSEL EQUATION”. Bulletin of Abai KazNPU. Series of Physical and Mathematical Sciences, vol. 82, no. 2, June 2023, pp. 90-99, doi:10.51889/2959-5894.2023.82.2.010.