@misc{indiciaed9183e2d3f37,
  title = {Exploration intensity map of the Upper Cretaceous D Sandstone, Denver basin, Colorado, Nebraska, and Wyoming},
  author = {Debra K. Higley and D. L. Gautier and Richard F. Mast},
  year = {1987},
  doi = {10.3133/ofr87351a},
  url = {https://pubs.usgs.gov/publication/ofr87351A},
  note = {Source identifier: ofr87351A}
}