N. Butris R, Shuker Jameel G. Periodic Solutions for Nonlinear System of Differential Equations of Third Order with Boundary Conditions. JES [Internet]. 2013 Mar. 1 [cited 2025 Sep. 10];26(1):126-39. Available from: https://edusj.uomosul.edu.iq/index.php/edusj/article/view/41376