DINH, Nguyen Van; TRI, Tran Duong. The Poincaré method for an oscillator with quadratic nonlinearity. <b>Vietnam Journal of Mechanics</b>, Hanoi, Vietnam, v. 26, n. 1, p. 23–30, 2004. DOI: 10.15625/0866-7136/26/1/5686. Disponível em: https://vjmech.vast.vn/vjmech/article/view/5686. Acesso em: 8 nov. 2025.