@misc{indiciae3998046f3767,
  title = {Physiography and surficial geology of the copper-nickel study region, northeastern Minnesota},
  author = {P. G. Olcott and D. I. Siegel},
  year = {1978},
  doi = {10.3133/wri7851},
  url = {https://pubs.usgs.gov/publication/wri7851},
  note = {Source identifier: wri7851}
}