HAI, Ninh Quang. Analysis of some nonlinear deterministic oscillators using extended averaged equation approach. <b>Vietnam Journal of Mechanics</b>, Hanoi, Vietnam, v. 27, n. 1, p. 32–40, 2005. DOI: 10.15625/0866-7136/27/1/5712. Disponível em: https://vjmech.vast.vn/vjmech/article/view/5712. Acesso em: 8 nov. 2025.