@misc{indiciae3b3fbc1167b3,
  title = {Geologic map of the Quebradillas quadrangle, Puerto Rico},
  author = {W. H. Monroe},
  year = {1967},
  doi = {10.3133/i498},
  url = {https://pubs.usgs.gov/publication/i498},
  note = {Source identifier: i498}
}