@misc{indiciae29bb9c00484a,
  title = {Geology and zinc-lead deposits in the Durango area, Dubuque County, Iowa},
  author = {Arthur E. Flint and C. Erwin Brown},
  year = {1955},
  doi = {10.3133/mf33},
  url = {https://pubs.usgs.gov/publication/mf33},
  note = {Source identifier: mf33}
}