@misc{indiciaec8df9be5b9df,
  title = {A digital geologic map database for the state of Oklahoma},
  author = {William D. Heran and Gregory N. Green and Douglas B. Stoeser},
  year = {2003},
  doi = {10.3133/ofr03247},
  url = {https://pubs.usgs.gov/publication/ofr03247},
  note = {Source identifier: ofr03247}
}