K. Srujan, Dr. S. Shiva Prasad, and Vinod Kumar. “A Three Phase UPS Systems Operating Under Nonlinear Loads With Modified SPWM Controller”. International Journal of Advance Engineering and Research Development (IJAERD), vol. 2, no. 9, Sept. 2015, pp. 70-76, https://ijaerd.org/index.php/IJAERD/article/view/1018.