WASET
    G. Kishor Babu and  B. Madhu Kiran,  Improving the Voltage Level in High Voltage Direct Current Systems by Using Modular Multilevel Converter.   journal   = {International Journal of Electronics and Communication Engineering}, [online]. World Academy of Science, Engineering and Technology.
    June 2019, vol. 151(7). 492 - 506
    [viewed 16 April 2024]. Available from: https://publications.waset.org/pdf/10010591.