@misc{indiciae2d320bb61f88,
  title = {Coal of the Denver Basin, Colorado. The South Park coal field, Colorado. The Colorado Springs coal field, Colorado. The Canon City coal field, Colorado. The Trinidad coal field, Colorado. Isolated coal fields in Santa Fe and San Miguel Counties, New Mexico. The Carthage Coal field, New Mexico. The coal field between San Mateo and Cuba, New Mexico},
  author = {G. C. Martin and Chester Wesley Washburne and M.I. Goldman and G. B. Richardson and James Gardner},
  year = {1910},
  doi = {10.3133/b381c},
  url = {https://pubs.usgs.gov/publication/b381C},
  note = {Source identifier: b381C}
}