A Fourth-Order Derivative-Free Operator Marching Method for Helmholtz Equation in Waveguides. Journal of Computational Mathematics, [S. l.], v. 25, n. 6, p. 719–729, 2021. Disponível em: https://www.global-sci.com/index.php/JCM/article/view/11861. Acesso em: 5 dec. 2025.