Nguyen, V. N., and N. H. Pham. “Carrier PWM Control of Cascade Multilevel Inverter for Three-Phase Four-Wire Shunt Active Filter”. Journal of Technical Education Science, vol. 5, no. 3, Sept. 2010, pp. 38-45, https://www.jte.edu.vn/index.php/jte/article/view/811.