Before revision:  In this paper, we study three specific COVID-19 epidemic control models: the susceptible, exposed, infectious, recovered (SEIR) model with vaccination control , the SEIR model with shield immunity control , and the susceptible, un-quarantined infected, quarantined infected, confirmed infected (SUQC) model with quarantine control.
After revision:  We study three specific COVID-19 epidemic control models: the susceptible, exposed, infectious, recovered (SEIR) model with vaccination control , the SEIR model with shield immunity control , and the susceptible, un-quarantined infected, quarantined infected, confirmed infected (SUQC) model with quarantine control.