Swift/BAT measurements of the cyclotron line energy decay in the accreting neutron star Hercules X-1: indication of an evolution of the magnetic field?D. Klochkov, R. Staubert, K. Postnov, J. Wilms, R. E. Rothschild and A. SantangeloA&A, 578 (2015) A88DOI: https://doi.org/10.1051/0004-6361/201526188
