Kusi, G.R., Bullo, T.A. and Duressa, G.F. 2021. Quartic Non-polynomial Spline Method for Singularly Perturbed Differential-difference Equation with Two Parameters. Journal of Engineering Advancements. 2, 02 (May 2021), 71–77. DOI:https://doi.org/10.38032/jea.2021.02.002.