@misc{indiciaedd60017973a3,
  title = {The U.S. Midcontinent: a new frontier for mineral exploration.},
  author = {W. P. Pratt and P.K. Sims},
  year = {1987},
  url = {https://pubs.usgs.gov/publication/70014743},
  note = {Source identifier: 70014743}
}