@misc{indiciaeaca75fcba8b7,
  title = {Maps showing extent and thickness of coal beds and amount of overburden on coal beds in the Salina quadrangle, Utah},
  author = {Robert J. Hackman},
  year = {1972},
  doi = {10.3133/i591i},
  url = {https://pubs.usgs.gov/publication/i591I},
  note = {Source identifier: i591I}
}