BUTRIS, R.; SALAHDIN YOUNIS, A. The investigation of solutions for nonlinear system of differential equations with boundary conditions. Journal of Education and Science (JES), [S. l.], v. 19, n. 3, p. 71–86, 2007. DOI: 10.33899/edusj.2007.51322. Disponível em: https://ojs.uomosul.edu.iq/index.php/edusj/article/view/23153. Acesso em: 6 aug. 2025.