@misc{indiciae125c37c6ac85,
  title = {Resource targets for advanced underground coal extraction systems},
  author = {Hoag, J. H. and Whipple, D. W. and Habib-Agahi, H. and Lavin, M. L.},
  year = {1982},
  url = {https://ntrs.nasa.gov/citations/19830002233},
  note = {Source identifier: 19830002233}
}