@misc{indiciaecab8301f571f,
  title = {Age of the Bedford Shale, Berea Sandstone, and Sunbury Shale in the Appalachian and Michigan basins, Pennsylvania, Ohio, and Michigan},
  author = {Wallace De Witt},
  year = {1970},
  doi = {10.3133/b1294g},
  url = {https://pubs.usgs.gov/publication/b1294G},
  note = {Source identifier: b1294G}
}