@misc{indiciae6e6b0f60e604,
  title = {Some linguloid shells from the late Devonian and early Carboniferous rocks of Pennsylvania and Ohio},
  author = {G.H. Girty},
  year = {1939},
  doi = {10.3133/pp193c},
  url = {https://pubs.usgs.gov/publication/pp193C},
  note = {Source identifier: pp193C}
}