@misc{indiciaea253acbeb1ff,
  title = {Shaded-relief and color shaded-relief maps of the Willamette Valley, Oregon},
  author = {R. W. Givler and Ray E. Wells},
  year = {2001},
  doi = {10.3133/ofr01294},
  url = {https://pubs.usgs.gov/publication/ofr01294},
  note = {Source identifier: ofr01294}
}