Model based on several references: 1. https://insightmaker.com/insight/4iVOp2JcrDSTBvqjER7pxM/TA-Pemsim-SEIR-Covid-19-Model 2. https://insightmaker.com/insight/5GiU0WZLpKCLGOoe6xeIhT/SEIR-COVID-19-New-Kl-1 3. https://insightmaker.com/insight/DaOeZ0N9RcgU1Q87ofIj8/COVID-19-SEIR-Model-for-Indonesia