@inproceedings{RaassenHuchtMilleretal.2008,
  author    = {A. J. J. Raassen and K. A. van der Hucht and N. A. Miller and Joseph P. Cassinelli},
  title     = {XMM-Newton observations of zeta Orionis (O9.7 Ib) : a collisional ionization equilibrium model},
  year      = {2008},
}