Adilaxmi, M., D. Bhargavi, and K. Phaneendra. “Numerical Solution of Singularly Perturbed Differential-Difference Equations Using Multiple Fitting Factors”. Communications in Mathematics and Applications 10, no. 4 (December 31, 2019): 681–691. Accessed July 3, 2024. https://rgnpublications.com/journals/index.php/cma/article/view/1129.