@misc{indiciaeaeb2bf3f0405,
  title = {Chemical and physical characterization of mine samples from Lakhra coal field, South Sind, Pakistan},
  author = {F.O. Simon and R.A. Khan and E.R. Landis and R.T. Hildebrand},
  year = {1987},
  doi = {10.3133/ofr87662},
  url = {https://pubs.usgs.gov/publication/ofr87662},
  note = {Source identifier: ofr87662}
}