@misc{indiciae23147cb0089b,
  title = {Reconnaissance map showing locations of possible sources of riprap in western North Dakota and in northwestern South Dakota},
  author = {P.E. Truesdell and G.S. Hilton},
  year = {1947},
  doi = {10.3133/mb20},
  url = {https://pubs.usgs.gov/publication/mb20},
  note = {Source identifier: mb20}
}