@misc{indiciaeb28ef45eb56f,
  title = {Minor element content of coal from Illinois beds 5 and 6 and their correlatives in Indiana and western Kentucky},
  author = {Peter Zubovic},
  year = {1960},
  doi = {10.3133/ofr60165},
  url = {https://pubs.usgs.gov/publication/ofr60165},
  note = {Source identifier: ofr60165}
}