H. MAHMOOD, A.; S. KARYAKOS, R.; H. SAADOON, L. Solvability Conditions For A system Of Nonhomogenous Differntial Equations Of The First Order. Journal of Education and Science (JES), [S. l.], v. 21, n. 2, p. 150–154, 2008. DOI: 10.33899/edusj.2008.51253. Disponível em: https://ojs.uomosul.edu.iq/index.php/edusj/article/view/24426. Acesso em: 7 aug. 2025.