Bui Tuan Anh, Trinh Manh Thang, and Bui Duy Thinh. “DESIGNING A FOUR-BALL FRICTION MACHINE CONTROL SYSTEM TO EVALUATE THE LUBRICANT QUALITY OF OIL AND ADDITIVE MIXTURE”. UTEHY Journal of Science and Technology, Vol. 38, June 2023, pp. 21-26, http://tapchi.utehy.edu.vn/index.php/jst/article/view/604.