@misc{indiciaec7b5a9f04b50,
  title = {Reference system characteristics for manned stopover missions to Mars and Venus},
  author = {Deerwester, J. M. and Norman, S. M.},
  year = {1971},
  url = {https://ntrs.nasa.gov/citations/19710009173},
  note = {Source identifier: 19710009173}
}