@misc{indiciae91d9aa733148,
  title = {Thermal Maturity of Pennsylvanian Coals and Coaly Shales, Eastern Shelf and Fort Worth Basin, Texas},
  author = {Paul C. Hackley and Edgar H. Guevara and Tucker F. Hentz and Robert W. Hook},
  year = {2007},
  doi = {10.3133/ofr20071312},
  url = {https://pubs.usgs.gov/publication/ofr20071312},
  note = {Source identifier: ofr20071312}
}