Yermekkyzy , L. . “VARIATIVE SOLUTION OF THE COEFFICIENT INVERSE PROBLEM FOR THE HEAT EQUATIONS”. Bulletin of the Abai KazNPU, the Series of "Physical and Mathematical Sciences&Quot;, vol. 72, no. 4, Dec. 2020, pp. 23-27, doi:10.51889/2020-4.1728-7901.03 .