@misc{indiciae71011309b209,
  title = {Bedrock geologic map of Springfield 1 degree by 2 degrees quadrangle, Missouri},
  author = {Mark A. Middendorf and Kenneth C. Thomson and G.L. Easson and H.S. Sumner},
  year = {1987},
  doi = {10.3133/mf1830d},
  url = {https://pubs.usgs.gov/publication/mf1830D},
  note = {Source identifier: mf1830D}
}