“On Frechet Differentiability of Invariant Torus for Nonlinear Countable System of Difference Equations Defined on an Infinite-Dimensional Torus and Containing Deviations of the Discrete Argument”. Neliniini Kolyvannya 6, no. 2 (June 29, 2003): 260–278. Accessed January 22, 2026. https://twinhead.imath.kiev.ua/index.php/nosc/article/view/265.