Mohamad Nor, A. F., M. Sulaiman, A. F. Abdul Kadir, and R. Omar. “Determining Voltage Stability Margin Values by Measuring the Hypotenuse Under PV and QV Curves”. International Journal of Electrical Engineering and Applied Sciences (IJEEAS), vol. 1, no. 1, Apr. 2018, pp. 25-30, https://ijeeas.utem.edu.my/ijeeas/article/view/3901.