@misc{indiciae8e02421b3dcf,
  title = {Manganese deposits of the Sweet Springs district, West Virginia and Virginia},
  author = {Harry Stephen Ladd},
  year = {1944},
  doi = {10.3133/b940g},
  url = {https://pubs.usgs.gov/publication/b940G},
  note = {Source identifier: b940G}
}