@misc{indiciaebb9c3441ab11,
  title = {Map of segregated Choctaw and Chickasaw Indian coal lands in Oklahoma},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {1940},
  doi = {10.3133/ofr404},
  url = {https://pubs.usgs.gov/publication/ofr404},
  note = {Source identifier: ofr404}
}