Yatim, M. H., et al. “Analysis of Symmetric and Asymmetric Multilevel Inverter Topologies Using Reduced Number of Switching Devices Circuit Structure”. International Journal of Engineering & Technology, vol. 7, no. 4.30, Nov. 2018, pp. 234-9, https://doi.org/10.14419/ijet.v7i4.30.22127.