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, [S. l.], v. 21, n. 2, p. 150–154, 2008. DOI: 10.33899/edusj.2008.51253. Disponível em: https://edusj.uomosul.edu.iq/index.php/edusj/article/view/42552. Acesso em: 10 sep. 2025.