Tjahjana, R. Heru, and Sutimin Sutimin. “Optimal Control Approach For HIV-1 Infection in CD4+T Cells With RTI and PI Treatments”. (IJCSAM) International Journal of Computing Science and Applied Mathematics, vol. 6, no. 2, Aug. 2020, pp. 42-45, https://journal.its.ac.id/index.php/ijcsam/article/view/4568.