@misc{indiciaeaa7d5318bd54,
  title = {Methods for local gravity field approximation},
  author = {Sailor, R. V. and Tait, K. S. and Leschack, A. R.},
  year = {1989},
  url = {https://ntrs.nasa.gov/citations/19900011216},
  note = {Source identifier: 19900011216}
}