Boichuk О. A. A Condition for the Existence of a Unique Green–Samoilenko Function for the Problem of Invariant Torus. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 53, n. 4, p. 556–559, 2001. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4277. Acesso em: 7 apr. 2025.