@misc{indiciae888949ea334a,
  title = {Preliminary geologic map of the Naguabo and part of the Punta Puerca quadrangles, Puerto Rico},
  author = {John W. M’Gonigle},
  year = {1977},
  doi = {10.3133/ofr77564},
  url = {https://pubs.usgs.gov/publication/ofr77564},
  note = {Source identifier: ofr77564}
}