Bukhari, S. S. H. ., and J.-S. . Ro. “Sub-Harmonic-Based Cost-Effective Brushless Wound Rotor Synchronous Machine Topology”. Applied Computational Electromagnetics Society Journal (ACES), vol. 38, no. 05, May 2023, pp. 371-6, doi:10.13052/2023.ACES.J.380510.