@misc{indiciae68c6c2b00708,
  title = {Tertiary geology of the coastal plains of Puerto Rico},
  author = {Alfred D. Zapp and Harlan Richard Bergquist and C.R. Thomas},
  year = {1948},
  doi = {10.3133/om85},
  url = {https://pubs.usgs.gov/publication/om85},
  note = {Source identifier: om85}
}