@misc{indiciaef45415500236,
  title = {Vertical variations of mercury in Pennsylvanian coal beds from Indiana},
  author = {Maria Mastalerz and A. Drobniak},
  year = {2005},
  doi = {10.1016/j.coal.2005.02.004},
  url = {https://pubs.usgs.gov/publication/70029554},
  note = {Source identifier: 70029554}
}