@misc{indiciae46b6c8e0a701,
  title = {First-order planetary theory. Perturbations in rectangular coordinates, Hansen's variables, longitude, and distance},
  author = {Hamid, S. E.},
  year = {1968},
  url = {https://ntrs.nasa.gov/citations/19690013796},
  note = {Source identifier: 19690013796}
}