@misc{indiciae671973746ab3,
  title = {The national coal-resources data system of the U.S. geological survey},
  author = {M.D. Carter},
  year = {1976},
  doi = {10.1016/0098-3004(76)90062-5},
  url = {https://pubs.usgs.gov/publication/70010350},
  note = {Source identifier: 70010350}
}