KULIK, V. L.; STEPANENKO, N. V. Alternating Lyapunov functions in the theory of linear extensions of dynamical systems on a torus. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 59, n. 4, p. 488–500, 2007. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3323. Acesso em: 6 dec. 2025.