@misc{indiciae2a16a7639105,
  title = {Isopach map of the interval from surface elevation to the top of the Pennsylvanian and Permian Minnelusa Formation and equivalents, Powder River basin, Wyoming and Montana},
  author = {B.L. Crysdale},
  year = {1990},
  doi = {10.3133/mf2140a},
  url = {https://pubs.usgs.gov/publication/mf2140A},
  note = {Source identifier: mf2140A}
}