@misc{indiciae28c1868b12f1,
  title = {Coal resources of Trinidad-Aguilar area, Las Animas and Huerfano Counties, Colorado},
  author = {R. L. Harbour and G. H. Dixon},
  year = {1959},
  doi = {10.3133/b1072g},
  url = {https://pubs.usgs.gov/publication/b1072G},
  note = {Source identifier: b1072G}
}