On the Error Estimate of Nonconforming Finite Element Approximation to the Obstacle Problem. Journal of Computational Mathematics, [S. l.], v. 21, n. 4, p. 481–490, 2003. Disponível em: https://www.global-sci.com/index.php/JCM/article/view/11573. Acesso em: 5 dec. 2025.