@misc{indiciae3e19e77298d6,
  title = {A continuous proportional low-thrust propulsion system},
  author = {Chen, J.-H. and Bull, J. and Debra, D. B.},
  year = {1990},
  url = {https://ntrs.nasa.gov/citations/19910042013},
  note = {Source identifier: 19910042013}
}