@misc{indiciae79a573cd0fe1,
  title = {Changes in stratigraphic nomenclature in the Cretaceous system, east-central Puerto Rico},
  author = {Reginald Peter Briggs},
  year = {1969},
  doi = {10.3133/b1274o},
  url = {https://pubs.usgs.gov/publication/b1274O},
  note = {Source identifier: b1274O}
}