KHIEM, Nguyen Tien. Spectral analysis of vibration in weakly non-linear systems. <b>Vietnam Journal of Mechanics</b>, Hanoi, Vietnam, v. 22, n. 3, p. 181–192, 2000. DOI: 10.15625/0866-7136/9974. Disponível em: https://vjmech.vast.vn/vjmech/article/view/9974. Acesso em: 8 nov. 2025.