Photon rings of spherically symmetric black holes and robust tests of non-Kerr metricsDOI: info:10.1103/PhysRevD.104.124058v. 104124058
Wielgus, Maciek. 2021. "Photon rings of spherically symmetric black holes and robust tests of non-Kerr metrics." Physical Review D, 104 124058. https://doi.org/10.1103/PhysRevD.104.124058.