@misc{indiciae124997063247,
  title = {Maps showing characteristics of the Isabela offshore sand deposit, northwestern Puerto Rico},
  author = {Juan L. Trias},
  year = {1990},
  doi = {10.3133/mf2136},
  url = {https://pubs.usgs.gov/publication/mf2136},
  note = {Source identifier: mf2136}
}