@misc{indiciae6abfef1d115d,
  title = {Bedrock topography of northwest Iowa},
  author = {R.E. Hansen},
  year = {1985},
  doi = {10.3133/ofr8597},
  url = {https://pubs.usgs.gov/publication/ofr8597},
  note = {Source identifier: ofr8597}
}