@misc{indiciae6849ef5c329d,
  title = {Upper Devonian biostratigraphy of Michigan Basin},
  author = {R.C. Gutschick and Charles Sandberg},
  year = {1991},
  doi = {10.1130/spe256-p155},
  url = {https://pubs.usgs.gov/publication/70206857},
  note = {Source identifier: 70206857}
}