@misc{indiciae1cb0eb2713d9,
  title = {Petrographic and geochemical contrasts and environmentally significant trace elements in marine-influenced coal seams, Yanzhou mining area, China},
  author = {Gaisheng Liu and P. Yang and Z. Peng and C. L. Chou},
  year = {2004},
  doi = {10.1016/j.jseaes.2003.07.003},
  url = {https://pubs.usgs.gov/publication/70026894},
  note = {Source identifier: 70026894}
}