Liu , LibinChen , Yanping and Liang , Ying. (2022). Numerical Analysis of a Nonlinear Singularly Perturbed Delay Volterra Integro-Differential Equation on an Adaptive Grid.
            <i>Journal of Computational Mathematics</i>. <i>40</i> (2).
            258-274.
         doi:10.4208/jcm.2008-m2020-0063