@misc{indiciaecf5684bcdf02,
  title = {Exploratory drilling in the Prairie du Chien Group of the Wisconsin zinc-lead district by the U.S. Geological Survey in 1949-1950},
  author = {Allen Van Heyl and Erwin J. Lyons and Allen F. Agnew},
  year = {1951},
  doi = {10.3133/cir131},
  url = {https://pubs.usgs.gov/publication/cir131},
  note = {Source identifier: cir131}
}