MATSUOKA, T. Braid invariants and instability of periodic solutions of time-periodic $2$-dimensional ODE’s. Topological Methods in Nonlinear Analysis, [S. l.], v. 14, n. 2, p. 261–274, 1999. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.1999.033. Acesso em: 29 mar. 2024.