K. H. AL-Jizani, “The Analytic Solutions of Nonlinear Generalized Pantograph Differential Equations of Higher Order Via Coupled Adomian-Homotopy Technique”, Iraqi Journal of Science, vol. 63, no. 11, pp. 4911–4917, Nov. 2022, doi: 10.24996/ijs.2022.63.11.27.