Slyusarchuk, V. V. (2001). Conditions for Instability of an Invariant Toroidal Manifold of a Discrete Dynamical System in a Banach Space. Ukrains’kyi Matematychnyi Zhurnal, 53(4), 572-576. Retrieved from https://umj.imath.kiev.ua/index.php/umj/article/view/4280