@article{Droulans:2010G/,
  author = "Droulans, Robert",
  title = "{GX 339-4: spectral variability of the hard X-ray emission}",
  doi = "10.22323/1.096.0053",
  journal = "PoS",
  year = 2010,
  volume = "extremesky2009",
  pages = "053"
}