@misc{indiciae9f285f09574b,
  title = {Trajectory optimization using regularized variables.},
  author = {Lewallen, J. M. and Szebehely, V. and Tapley, B. D.},
  year = {1969},
  url = {https://ntrs.nasa.gov/citations/19690059184},
  note = {Source identifier: 19690059184}
}