@misc{indiciae9bac17a8417e,
  title = {Exploration intensity map of the Cretaceous J Sandstone, Denver Basin, Colorado, Nebraska, and Wyoming},
  author = {Debra K. Higley and D. L. Gautier and Richard F. Mast},
  year = {1987},
  doi = {10.3133/ofr872},
  url = {https://pubs.usgs.gov/publication/ofr872},
  note = {Source identifier: ofr872}
}