@misc{indiciae0e61f1c1c5f2,
  title = {Iteration procedures for indirect trajectory optimization methods.},
  author = {Lewallen, J. M. and Tapley, B. D. and Williams, S. D.},
  year = {1968},
  url = {https://ntrs.nasa.gov/citations/19680040422},
  note = {Source identifier: 19680040422}
}