Mіtrоpоlskу YA, Fоdchuk VI. Substantiation of the averaging method for differential-difference equations in the Hilbert space . Ukr. Mat. Zhurn. [Internet]. 1971 Oct. 26 [cited 2025 Dec. 5];23(6):745-52. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/8621