Mіtrоpоlskу Yu. A.; Fоdchuk V. I. Substantiation of the averaging method for differential-difference equations in the Hilbert space . Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 23, n. 6, p. 745–752, 1971. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/8621. Acesso em: 6 dec. 2025.