@misc{indiciae7ef54b86a1e9,
  title = {The Piedmont landscape of Maryland: a new look at an old problem.},
  author = {J. E. Costa and E.T. Cleaves},
  year = {2006},
  doi = {10.1002/esp.3290090107},
  url = {https://pubs.usgs.gov/publication/70013916},
  note = {Source identifier: 70013916}
}