Scalar instabilities inside the extremal dyonic Kerr–Sen black hole: novel exact solutions and Chronology Protection ConjectureDavid Senjaya, Teephatai Bunyaratavej and Piyabut BurikhamEur. Phys. J. C, 85 6 (2025) 654DOI: https://doi.org/10.1140/epjc/s10052-025-14365-w