@misc{indiciaed29a215c6093,
  title = {Geologic map of the Yabucoa and Punta Tuna quadrangles, Puerto Rico},
  author = {C.L. Roberts and C. M. Cram and M. H. Pease and M. S. Tischler},
  year = {1979},
  doi = {10.3133/i1086},
  url = {https://pubs.usgs.gov/publication/i1086},
  note = {Source identifier: i1086}
}