ULX spectra revisited: Accreting, highly magnetized neutron stars as the engines of ultraluminous X-ray sourcesFilippos Koliopanos, Georgios Vasilopoulos, Olivier Godet, Matteo Bachetti, Natalie A. Webb and Didier BarretA&A, 608 (2017) A47DOI: https://doi.org/10.1051/0004-6361/201730922