Poletaev G. S. “Convolution-Type Integral Equation With Two Kernels and Its Abstract Analog”. Ukrains’kyi Matematychnyi Zhurnal 44, no. 8 (September 8, 1992): 1065-1078. Accessed November 24, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/8035.