M. F. Gorodnii and A. Y. Dorogovtsev, “Bounded solutions of one class of nonlinear operator difference equations”, Ukr. Mat. Zhurn., vol. 47, no. 7, pp. 890–896, Jul. 1995, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/5483