LE, B. H.; THUY, T. M. Optimal design for eigen-frequencies of a longitudinal bar using Pontryagin’s maximum principle considering the influence of concentrated mass. Vietnam Journal of Mechanics, Hanoi, Vietnam, v. 39, n. 1, p. 1–12, 2017. DOI: 10.15625/0866-7136/6058. Disponível em: https://vjs.ac.vn/index.php/vjmech/article/view/6058. Acesso em: 20 apr. 2024.