@misc{indiciae60f9302dc906,
  title = {Geologic considerations in underground coal mining system design},
  author = {Camilli, F. A. and Maynard, D. P. and Mangolds, A. and Harris, J.},
  year = {1981},
  url = {https://ntrs.nasa.gov/citations/19820003643},
  note = {Source identifier: 19820003643}
}