@misc{indiciaebc480fc276b0,
  title = {Preliminary map of lead provinces in the conterminous United States},
  author = {Edwin Wilson Tooker and H. T. Morris},
  year = {1980},
  doi = {10.3133/ofr79576p},
  url = {https://pubs.usgs.gov/publication/ofr79576P},
  note = {Source identifier: ofr79576P}
}