@misc{indiciae5dc68e13c18f,
  title = {A stable carbon isotope and biological marker study of Polish bituminous coals and carbonaceous shales},
  author = {M.J. Kotarba and J.L. Clayton},
  year = {2003},
  doi = {10.1016/s0166-5162(03)00082-x},
  url = {https://pubs.usgs.gov/publication/70025809},
  note = {Source identifier: 70025809}
}