@misc{indiciaeb1df90a996e0,
  title = {Geologic map of the Harper Quadrangle, Liberia},
  author = {M. R. Brock and A.H. Chidester and M.W.G. Baker},
  year = {1977},
  doi = {10.3133/i780d},
  url = {https://pubs.usgs.gov/publication/i780D},
  note = {Source identifier: i780D}
}