@misc{indiciaef2a905f2c976,
  title = {Geologic map of the Marble Hill Quadrangle, Bollinger County, Missouri},
  author = {D.H. Amos},
  year = {1987},
  doi = {10.3133/mf1900},
  url = {https://pubs.usgs.gov/publication/mf1900},
  note = {Source identifier: mf1900}
}