@misc{indiciae8a8f54b93dfe,
  title = {Callovian (Jurassic) ammonites from the United States and Alaska; Part 1, Western interior United States},
  author = {R. W. Imlay},
  year = {1953},
  doi = {10.3133/pp249a},
  url = {https://pubs.usgs.gov/publication/pp249A},
  note = {Source identifier: pp249A}
}