@misc{indiciae00dda51260ae,
  title = {Borehole gravity surveys of the U.S. Geological Survey (1963-1975); brief history and basic data},
  author = {L. A. Beyer},
  year = {1980},
  doi = {10.3133/ofr80903},
  url = {https://pubs.usgs.gov/publication/ofr80903},
  note = {Source identifier: ofr80903}
}