@misc{indiciaeb591e22c9a73,
  title = {An approximation method for determination of propulsion requirements associated with low thrust coplanar orbital transfer in a central force field under negligible external perturbations},
  author = {Duck, K. I.},
  year = {1963},
  url = {https://ntrs.nasa.gov/citations/19660022768},
  note = {Source identifier: 19660022768}
}