H. MAHMOOD, AKRAM, RAID S. KARYAKOS, and LAMYAA H. SAADOON. 2008. “Solvability Conditions For A System Of Nonhomogenous Differntial Equations Of The First Order”. Journal of Education and Science 21 (2):150-54. https://doi.org/10.33899/edusj.2008.51253.