@misc{indiciaeabf8121012b8,
  title = {Mineral map of the Bopolu Quadrangle, Liberia},
  author = {W. L. Coonrad},
  year = {1979},
  doi = {10.3133/ofr791516},
  url = {https://pubs.usgs.gov/publication/ofr791516},
  note = {Source identifier: ofr791516}
}