@misc{indiciae3ddb94246fae,
  title = {Techniques for increasing the efficiency of Earth gravity calculations for precision orbit determination},
  author = {Smith, R. L. and Lyubomirsky, A. S.},
  year = {1981},
  url = {https://ntrs.nasa.gov/citations/19820002196},
  note = {Source identifier: 19820002196}
}