@misc{indiciaeaa1fb23a90f0,
  title = {Geology and zinc-lead deposits in the Couler Valley area, Dubuque County, Iowa},
  author = {C. Erwin Brown and L.G. Collins and Percy Crosby},
  year = {1955},
  doi = {10.3133/mf42},
  url = {https://pubs.usgs.gov/publication/mf42},
  note = {Source identifier: mf42}
}