@misc{indiciaea69ff1c90d09,
  title = {Preliminary map showing geology and construction materials of the Wray no. 3 and Wray no. 4 quadrangles, Colorado-Nebraska},
  author = {Dorothy R. Townsend and Jessie M. Tompkin},
  year = {1951},
  doi = {10.3133/ofr5111},
  url = {https://pubs.usgs.gov/publication/ofr5111},
  note = {Source identifier: ofr5111}
}