Vo Thi Huong, Nguyen Ngoc Quang, Chu Thi Thanh Tho, Pham Ngoc Thang, and Do Thanh Hieu. “AN IMPROVED P&O MAXIMUM POWER POINT TRACKING METHOD FOR PHOTOVOLTAIC SYSTEMS UNDER RAPIDLY CHANGING IRRADIANCE CONDITIONS”. UTEHY Journal of Applied Science and Technology, Vol. 19, Oct. 2018, pp. 22-28, http://jst.utehy.edu.vn/index.php/jst/article/view/83.