Anakira, N., M. J. Mohammed, Irianto Irianto, Ala Amourah, and osama Oqilat. “Exact Solution of System of Multi-Photograph Type Delay Differential Equations Via New Algorithm Based on Homotopy Perturbation Method”. Results in Nonlinear Analysis, vol. 7, no. 2, June 2024, pp. 187-9, https://nonlinear-analysis.com/index.php/pub/article/view/406.