Dr. Alejandro Vargas López, and Ing. Mariana Torres Delgado. “Distributed Secondary Voltage and Frequency Control in Islanded AC Microgrids Using a Fixed-Time Observer Framework”. International Research Journal of Computer and Electronics Engineering, vol. 8, no. 2, June 2021, pp. 40-46, https://urgcee.org/index.php/ircee/article/view/61.