@misc{indiciae4b99b9e4ff93,
  title = {Petrographic and Vitrinite Reflectance Analyses of a Suite of High Volatile Bituminous Coal Samples from the United States and Venezuela},
  author = {Paul C. Hackley and Jonathan J. Kolak},
  year = {2008},
  doi = {10.3133/ofr20081230},
  url = {https://pubs.usgs.gov/publication/ofr20081230},
  note = {Source identifier: ofr20081230}
}