@misc{indiciaeb16050754641,
  title = {Petrology of the Eagle Sandstone, Bearpaw Mountains area, north-central Montana},
  author = {Donald L. Gautier},
  year = {1981},
  doi = {10.3133/b1521},
  url = {https://pubs.usgs.gov/publication/b1521},
  note = {Source identifier: b1521}
}