Tawfiq, Luma N. M., and Samaher M. Yassien. “Solution of High Order Ordinary Boundary Value Problems Using Semi-Analytic Technique”. Ibn AL-Haitham Journal For Pure and Applied Sciences, vol. 26, no. 1, Apr. 2017, pp. 281-9, https://doi.org/10.30526/26.1.535.