@misc{indiciaed348bba0571a,
  title = {Hydrogeologic unit map of the Piedmont and Blue Ridge provinces of North Carolina},
  author = {Charles C. Daniel and R.A. Payne},
  year = {1990},
  doi = {10.3133/wri904035},
  url = {https://pubs.usgs.gov/publication/wri904035},
  note = {Source identifier: wri904035}
}