Sakthivel A, Vikniswaran M, Selva Bharathi V, and Vikash B. “Voltage Control Based Five-Level Packed U-Cell Inverter”. International Journal of Advance Research in Engineering, Science & Technology, vol. 5, no. 3, Mar. 2018, pp. 782-6, https://ijarest.org/index.php/ijarest/article/view/1343.