@misc{indiciae121647ce8651,
  title = {Bedrock topography of west-central Iowa},
  author = {R.E. Hansen and D. L. Runkle},
  year = {1986},
  doi = {10.3133/i1688},
  url = {https://pubs.usgs.gov/publication/i1688},
  note = {Source identifier: i1688}
}