@misc{indiciae07f83a239b30,
  title = {The ancient oxygen exosphere of Mars - Implications for atmosphere evolution},
  author = {Zhang, M. H. G. and Luhmann, J. G. and Bougher, S. W. and Nagy, A. F.},
  year = {1993},
  url = {https://ntrs.nasa.gov/citations/19930060265},
  note = {Source identifier: 19930060265}
}