@misc{indiciaee75dfecccaf5,
  title = {Hydrogeologic map of Puerto Rico and adjacent islands},
  author = {Reginald Peter Briggs and J. P. Akers},
  year = {1965},
  doi = {10.3133/ha197},
  url = {https://pubs.usgs.gov/publication/ha197},
  note = {Source identifier: ha197}
}