Petrosyan, A. H., and L. G. Khachatryan. “ABOUT EXPANSION BY EIGEN FUNCTIONS SELF-ADJOINT DIFFERENTIAL OPERATOR’S WITH COEFFICIENTS HAVING PRECISE BEHAVIOUR IN INFINITY”. Proceedings of the YSU A: Physical and Mathematical Sciences 38, no. 1 (203) (December 28, 2003): 22–27. Accessed November 23, 2024. https://journals.ysu.am/index.php/proceedings-phys-math/article/view/vol38_no1_2004_pp022-026.