@misc{indiciaeac84052ab1fc,
  title = {Preliminary map of nickel provinces in the conterminous United States},
  author = {Edwin Wilson Tooker and Henry Rowland Cornwall},
  year = {1979},
  doi = {10.3133/ofr79576e},
  url = {https://pubs.usgs.gov/publication/ofr79576E},
  note = {Source identifier: ofr79576E}
}