@misc{indiciae1e36520db072,
  title = {Determination of nitrogen in coal macerals using electron microprobe technique-experimental procedure},
  author = {Maria Mastalerz and L.W. Gurba},
  year = {2001},
  doi = {10.1016/s0166-5162(01)00024-6},
  url = {https://pubs.usgs.gov/publication/70023283},
  note = {Source identifier: 70023283}
}