@misc{indiciaebe7ce9ef31a1,
  title = {Automated generation of shaded relief in aeronautical charts},
  author = {Donna K. Scholz and S. W. Doescher and R. A. Hoover},
  year = {1987},
  url = {https://pubs.usgs.gov/publication/70231669},
  note = {Source identifier: 70231669}
}