Cannizzaro, E., Caputo, A., Sberna, L., & Pani, P. (2021). Plasma-photon interaction in curved spacetime I: formalism and quasibound states around nonspinning black holes. Physical Review D, 103, 124018. Retrieved from https://publications.mppmu.mpg.de/?action=search&mpi=MPP-2020-221.