Uwaheren, O. A., A. F. Adebisi, and O. A. Taiwo. “Perturbed Collocation Method For Solving Singular Multi-Order Fractional Differential Equations of Lane-Emden Type”. Journal of the Nigerian Society of Physical Sciences, Vol. 2, no. 3, Aug. 2020, pp. 141-8, doi:10.46481/jnsps.2020.69.