S. Ott, I. Roasto, D. Vinnikov, and T. Lehtla, “Analytical and Experimental Investigation of Neutral Point Clamped Quasi-Impedance-Source Inverter”, ECCE, vol. 29, no. 1, pp. 113–118, Jan. 2011, doi: 10.2478/v10144-011-0019-5.