@misc{indiciaea60971559118,
  title = {Geology of the Dubuque South quadrangle, Iowa-Illinois},
  author = {C. Ervin Brown and Jesse W. Whitlow},
  year = {1960},
  doi = {10.3133/b1123a},
  url = {https://pubs.usgs.gov/publication/b1123A},
  note = {Source identifier: b1123A}
}