@misc{indiciae2c4f43249265,
  title = {Space transportation - Options and opportunities},
  author = {Loftus, J. P., Jr. and Ried, R. C. and Bristow, R. B.},
  year = {1988},
  url = {https://ntrs.nasa.gov/citations/19890039013},
  note = {Source identifier: 19890039013}
}