@misc{indiciaea33f3fa5e19d,
  title = {Experimental digital shaded-relief maps of Arizona},
  author = {R. M. Batson},
  year = {1990},
  doi = {10.3133/i1821},
  url = {https://pubs.usgs.gov/publication/i1821},
  note = {Source identifier: i1821}
}