@misc{indiciae989717b33d1f,
  title = {Source beds of petroleum in the Denver Basin},
  author = {Paul J. Swetland and Jerry L. Clayton},
  year = {1976},
  doi = {10.3133/ofr76572},
  url = {https://pubs.usgs.gov/publication/ofr76572},
  note = {Source identifier: ofr76572}
}