@misc{indiciaed2b7efc9b5c5,
  title = {PROTON MICROPROBE ANALYSIS OF TRACE-ELEMENT VARIATIONS IN VITRINITES IN THE SAME AND DIFFERENT COAL BEDS.},
  author = {J.A. Minkin and E. C. T. Chao and Herma Blank and F.T. Dulong},
  year = {1987},
  url = {https://pubs.usgs.gov/publication/70015225},
  note = {Source identifier: 70015225}
}