@misc{indiciae9b16bb4bd18f,
  title = {Geology of the Florida quadrangle, Puerto Rico},
  author = {Arthur E. Nelson and Watson Hiner Monroe},
  year = {1966},
  doi = {10.3133/b1221c},
  url = {https://pubs.usgs.gov/publication/b1221C},
  note = {Source identifier: b1221C}
}