@misc{indiciae0dce7620b778,
  title = {Geologic map of the Laurium quadrangle, Michigan},
  author = {H. R. Cornwall and J.C. Wright},
  year = {1956},
  doi = {10.3133/mf47},
  url = {https://pubs.usgs.gov/publication/mf47},
  note = {Source identifier: mf47}
}