SON, Nguyen Hoai. An enforced essential boundary condition by penalty method in the element-free Galerkin (EFG) methods. <b>Vietnam Journal of Mechanics</b>, Hanoi, Vietnam, v. 31, n. 2, p. 122–132, 2009. DOI: 10.15625/0866-7136/31/2/5489. Disponível em: https://vjmech.vast.vn/vjmech/article/view/5489. Acesso em: 8 nov. 2025.