@article{Staubert:2015xQ,
  author = "Staubert, Ruediger",
  title = "{Hercules X-1 - another ’first’: long-term decay of the cyclotron line energy}",
  doi = "10.22323/1.228.0024",
  journal = "PoS",
  year = 2015,
  volume = "Integral2014",
  pages = "024"
}