@misc{indiciae9b2fe0ad2c75,
  title = {Ground-based upward extrapolated gravity data for use in testing the aerial profiling of terrain system (APTS)},
  author = {T.G. Hildenbrand and R.P. Kucks and W. F. Hanna},
  year = {1984},
  doi = {10.3133/ofr84775},
  url = {https://pubs.usgs.gov/publication/ofr84775},
  note = {Source identifier: ofr84775}
}