Side, Syafruddin, Irwan Irwan, Muhammad Rifandi, Muhammad Pratama, Ruliana Ruliana, and Nor Zila Hamid. 2022. “Optimum Control of SEIR Model on COVID-19 Spread With Delay Time and Vaccination Effect in South Sulawesi Province”. Jurnal Varian 6 (1), 11 - 24. https://doi.org/https://doi.org/10.30812/varian.v6i1.1882.