@misc{indiciaeb2347a1f0439,
  title = {Karst in the United States: A digital map compilation and database},
  author = {David J. Weary and Daniel H. Doctor},
  year = {2014},
  doi = {10.3133/ofr20141156},
  url = {https://pubs.usgs.gov/publication/ofr20141156},
  note = {Source identifier: ofr20141156}
}