@misc{indiciaef87f3a87563b,
  title = {Digital maps and figures on CD-ROM for Mineral and energy resource assessment of the Helena National Forest, west-central Montana},
  author = {Gregory N. Green and Russell G. Tysdal},
  year = {1997},
  doi = {10.3133/ofr96683b},
  url = {https://pubs.usgs.gov/publication/ofr96683B},
  note = {Source identifier: ofr96683B}
}