@misc{indiciae092c3f192b21,
  title = {Some engineering geologic factors controlling coal mine subsidence in Utah and Colorado},
  author = {C. Richard Dunrud},
  year = {1976},
  doi = {10.3133/pp969},
  url = {https://pubs.usgs.gov/publication/pp969},
  note = {Source identifier: pp969}
}