@misc{indiciae08669185181e,
  title = {Geologic map of the Friedheim Quadrangle, Cape Girardeau, Bollinger, and Perry counties, Missouri},
  author = {D.H. Amos},
  year = {1987},
  doi = {10.3133/mf1905},
  url = {https://pubs.usgs.gov/publication/mf1905},
  note = {Source identifier: mf1905}
}