@misc{indiciaef6aee10096d3,
  title = {Analytic solution for optimal two-impulse 180 deg transfer between noncoplanar orbits and the optimal orientation of the transfer plane},
  author = {Sun, F. T.},
  year = {1969},
  url = {https://ntrs.nasa.gov/citations/19700036798},
  note = {Source identifier: 19700036798}
}