@misc{indiciaed58943577255,
  title = {Geologic map of the Zwedru Quadrangle, Liberia},
  author = {E. R. Force and H. M. Beikman},
  year = {1977},
  doi = {10.3133/i777d},
  url = {https://pubs.usgs.gov/publication/i777D},
  note = {Source identifier: i777D}
}