@misc{indiciaea1af91f59fa9,
  title = {Geologic map of Great Sand Dunes National Park, Colorado},
  author = {Richard F. Madole and D. Paco VanSistine and Joseph H. Romig},
  year = {2016},
  doi = {10.3133/sim3362},
  url = {https://pubs.usgs.gov/publication/sim3362},
  note = {Source identifier: sim3362}
}