@misc{indiciae806bf18d0076,
  title = {Coal Rank and Stratigraphy of Pennsylvanian Coal and Coaly Shale Samples, Young County, North-Central Texas},
  author = {Edgar H. Guevara and Caroline Breton and Paul C. Hackley},
  year = {2007},
  doi = {10.3133/ofr20071313},
  url = {https://pubs.usgs.gov/publication/ofr20071313},
  note = {Source identifier: ofr20071313}
}