Singh, R. P., and Y. N. Reddy. “A Fitted Second Order Special Finite Difference Method for Singularly Perturbed Differential- Difference Equations Exhibiting Dual Layers”. Journal of Informatics and Mathematical Sciences, vol. 12, no. 3, Sept. 2020, pp. 223-32, doi:10.26713/jims.v12i3.1430.