Andrusiak, Ivanna, and Oksana Brodyak. “Integral Representations Of Positive Definite Kernels For Second-Order Elliptic Operators”. PRECARPATHIAN BULLETIN OF THE SHEVCHENKO SCIENTIFIC SOCIETY. Number, no. 22(83), Apr. 2026, pp. 18-28, doi:10.31471/2304-7399-2026-22(83)-18-28.