The application of sample pooling for mass screening of SARS-CoV-2 in an outbreak of COVID-19 in Vietnam by Thanh, TT, Nhan, NTT, Mai, HK, Trieu, NB, Huy, LX, Thuy, HTT, Chung, LT, Anh, NN, Hong, NTT, Thang, BT, Thu, NTH, Chi, LTK, Hanh, NT, Hoang, NH, Chau, NVV, Thwaites, G, Hung, DT, Tan, LV, Yen, NTK