SIDE, S.; IRWAN, I.; RIFANDI, M.; PRATAMA, M.; RULIANA, R.; HAMID, N. Z. Optimum Control of SEIR Model on COVID-19 Spread with Delay Time and Vaccination Effect in South Sulawesi Province. Jurnal Varian, v. 6, n. 1, p. 11 - 24, 13 nov. 2022.