@misc{indiciae290e104f2467,
  title = {Map showing approximate eastern limit of commercial oil and gas fields in relation to structural features and physiographic provinces in the Appalachian region},
  author = {K.C. Bayer},
  year = {1982},
  doi = {10.3133/oc121},
  url = {https://pubs.usgs.gov/publication/oc121},
  note = {Source identifier: oc121}
}