@misc{indiciae460617c5a525,
  title = {Shaded relief map of US topography from digital elevations},
  author = {R.J. Pike and G.P. Thelin},
  year = {2011},
  doi = {10.1029/89eo00291},
  url = {https://pubs.usgs.gov/publication/70014939},
  note = {Source identifier: 70014939}
}