@misc{indiciae573f6de07e98,
  title = {Recreation impacts to cliff resources in the Potomac Gorge: Final report, June 2011},
  author = {Jeffrey L. Marion and C. Carr and C.A. Davis},
  year = {2011},
  url = {https://pubs.usgs.gov/publication/70004877},
  note = {Source identifier: 70004877}
}