Hojeen M. Haji, Raad N. Butris, Hezha H. Abdulkareem, Dlovan H. Omar. 2022. “Periodic Solution for Nonlinear Second Order Differential Equation System”. Turkish Journal of Computer and Mathematics Education (TURCOMAT) 13 (03):324-34. https://doi.org/10.17762/turcomat.v13i03.12968.