PYATETSKAYA, E. V. Invariant tori of linear extensions which do not have Green’s functions. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 45, n. 4, p. 520–524, 1993. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5839. Acesso em: 5 dec. 2025.