@misc{indiciae47d20993fd3e,
  title = {Aeromagnetic map of the Harper quadrangle, Liberia},
  author = {John Charles Behrendt and Cletus S. Wotorson},
  year = {1971},
  doi = {10.3133/ofr7123},
  url = {https://pubs.usgs.gov/publication/ofr7123},
  note = {Source identifier: ofr7123}
}