@misc{indiciae0099c3cfba3c,
  title = {Coking coal of the United States—Modern and historical coking coal mining locations and chemical, rheological, petrographic, and other data from modern samples},
  author = {Michael H. Trippi and Leslie F. Ruppert and Cortland F. Eble and James C. Hower},
  year = {2021},
  doi = {10.3133/ofr20201113},
  url = {https://pubs.usgs.gov/publication/ofr20201113},
  note = {Source identifier: ofr20201113}
}