@misc{indiciaeca66620a13f8,
  title = {Coal resources of Lawrence County, Pennsylvania},
  author = {J. A. Van Lieu and E. D. Patterson},
  year = {1964},
  doi = {10.3133/b1143b},
  url = {https://pubs.usgs.gov/publication/b1143B},
  note = {Source identifier: b1143B}
}