@misc{indiciae375b1f7a6546,
  title = {Structure of the Berea oil sand in the Summerfield quadrangle, Guernsey, Noble, and Monroe Counties, Ohio},
  author = {D. D. Condit},
  year = {1916},
  doi = {10.3133/b621n},
  url = {https://pubs.usgs.gov/publication/b621N},
  note = {Source identifier: b621N}
}