Dao, Viet Hung, Dang Hung Phan, Thi Nhung Dinh, Duy Hai Vu, and Quang Dan Chu. 2018. “A New Method of Measuring Impedance Cardiography for Cardiac Output Estimation by Directly Digitizing the High Frequency Modulated Signal at Lower Sampling Rate”. Old Journal, no. 131C (November):94-99. https://jst.vn/index.php/old/article/view/709.