@misc{indiciaec48e55444505,
  title = {Maps showing composition of surficial sediments on the insular shelf of southwestern Puerto Rico},
  author = {Gerald L. Shideler},
  year = {1980},
  doi = {10.3133/mf1258},
  url = {https://pubs.usgs.gov/publication/mf1258},
  note = {Source identifier: mf1258}
}