@misc{indiciae332ee215c576,
  title = {Geologic map of the Roberts Mountain quadrangle, Lewis and Clark County, Montana},
  author = {Robert George Schmidt and C.P. Strong},
  year = {1972},
  doi = {10.3133/gq977},
  url = {https://pubs.usgs.gov/publication/gq977},
  note = {Source identifier: gq977}
}