@misc{indiciaea0df70055db9,
  title = {Coal geology and assessment of coal resources and reserves in the Powder River Basin, Wyoming and Montana},
  author = {James A. Luppens and David C. Scott and Jon Haacke and Lee M. Osmonson and Paul E. Pierce},
  year = {2015},
  doi = {10.3133/pp1809},
  url = {https://pubs.usgs.gov/publication/pp1809},
  note = {Source identifier: pp1809}
}