@misc{indiciae926ba0ca8bbe,
  title = {Slope map of the Alexander quadrangle, Arkansas},
  author = {U.S. Geological Survey},
  year = {1978},
  doi = {10.3133/70210551},
  url = {https://pubs.usgs.gov/publication/70210551},
  note = {Source identifier: 70210551}
}