@misc{indiciae25b183b3ce58,
  title = {Ensuring flat cuts in longwall mining},
  author = {Campbell, R. A. and Currie, J. R. and Deaton, E. T. and Kissel, R. R.},
  year = {1979},
  url = {https://ntrs.nasa.gov/citations/19790000118},
  note = {Source identifier: 19790000118}
}