“A Comparative Study of Tumor Regression Efficiency under the Impact of Cytokines Interleukin-21 and Interleukin-2 for Cancer Treatment Cultured With Chemo - Immunotherapy: A Mathematical Modeling Approach”. Punjab University Journal of Mathematics, vol. 50, no. 2, June 2018, pp. 66-81, https://pujm.pu.edu.pk/index.php/pujm/article/view/130.