MartynyukD. I., PerestyukN. A., and SamoilenkoA. M. “Reducibility of Nonlinear Almost Periodic Systems of Difference Equations on an Infinite-Dimensional Torus”. Ukrains’kyi Matematychnyi Zhurnal 46, no. 9 (September 25, 1994): 1216–1223. Accessed July 27, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/5638.