@misc{indiciae1c05595a0903,
  title = {Some necessary conditions for optimal fixed- time powered transfers with multiple coasts and thrusts between circular orbits.},
  author = {Handelsman, M.},
  year = {1968},
  url = {https://ntrs.nasa.gov/citations/19680063610},
  note = {Source identifier: 19680063610}
}