@misc{indiciaea9a82bf95ee8,
  title = {Mineral deposits of Maryland, excluding fuels, sand, and gravel},
  author = {Nancy C. Pearre},
  year = {1961},
  doi = {10.3133/mr12},
  url = {https://pubs.usgs.gov/publication/mr12},
  note = {Source identifier: mr12}
}