I. D. . Mardanov, “Existence of the solution family of a system of linear difference equations with an argument deviation ”, Ukr. Mat. Zhurn., vol. 44, no. 7, pp. 988–991, Aug. 1992, Accessed: Feb. 17, 2026. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/8132