DINH, N. V. The Poincare method for a strongly nonlinear Duffing oscillator. Vietnam Journal of Mechanics, Hanoi, Vietnam, v. 25, n. 1, p. 19–25, 2003. DOI: 10.15625/0866-7136/25/1/6575. Disponível em: https://vjs.ac.vn/index.php/vjmech/article/view/6575. Acesso em: 27 apr. 2024.