@misc{indiciae8593c079bc64,
  title = {Map of Kansas showing the oil and gas fields and geologic ages of the producing formations in the fields},
  author = {Olive C. Postley},
  year = {1940},
  doi = {10.3133/70211266},
  url = {https://pubs.usgs.gov/publication/70211266},
  note = {Source identifier: 70211266}
}