E. V. Cheremnikh, “On certain resolvent convergence of one non-local problem to a problem with spectral parameter in boundary condition”, MFAT, vol. 14, no. 4, pp. 302–313, Dec. 2008, Accessed: Feb. 04, 2026. [Online]. Available: https://zen.imath.kiev.ua/index.php/mfat/article/view/393