@misc{indiciae7f53dc876733,
  title = {Exploratory drilling for evidence of zinc and lead ore in Dubuque County, Iowa},
  author = {A. E. Flint and C. Erwin Brown},
  year = {1956},
  doi = {10.3133/b1027k},
  url = {https://pubs.usgs.gov/publication/b1027K},
  note = {Source identifier: b1027K}
}