@misc{indiciae07199bb5544e,
  title = {Sand-sized heavy-mineral distributions in offshore insular shelf sediments of north-central Puerto Rico},
  author = {Gretchen Luepke and L. J. Poppe},
  year = {1993},
  doi = {10.3133/ofr93341},
  url = {https://pubs.usgs.gov/publication/ofr93341},
  note = {Source identifier: ofr93341}
}