@misc{indiciae8fae2092ebcf,
  title = {Geologic map of the Penuelas and Punta Cuchara quadrangles, Puerto Rico},
  author = {R.D. Krushensky and W. H. Monroe},
  year = {1978},
  doi = {10.3133/i1042},
  url = {https://pubs.usgs.gov/publication/i1042},
  note = {Source identifier: i1042}
}