OBINWANNE, E. E.; OKEKE, A. R. On Application of Lyapunov and Yoshizawa’s Theorems on Stability, Asymptotic Stability, Boundaries and Periodicity of Solutions of Duffing’s Equation. Asian Journal of Applied Sciences, [S. l.], v. 2, n. 6, 2014. Disponível em: https://www.ajouronline.com/index.php/AJAS/article/view/2034. Acesso em: 16 apr. 2024.