@misc{indiciae1750596a67a3,
  title = {Bedrock topography of northwest Iowa},
  author = {R.E. Hansen and D. L. Runkle},
  year = {1986},
  doi = {10.3133/i1726},
  url = {https://pubs.usgs.gov/publication/i1726},
  note = {Source identifier: i1726}
}