@misc{indiciae490add040fac,
  title = {Changes in population and agricultural land in conterminous United States counties, 1790 to 1997},
  author = {Pamela J. Waisanen and Norman B. Bliss},
  year = {2002},
  doi = {10.1029/2001gb001843},
  url = {https://pubs.usgs.gov/publication/70024196},
  note = {Source identifier: 70024196}
}