@misc{indiciae08e19d15395f,
  title = {Toxic substances from coal combustion - A comprehensive assessment, phase II: Element modes of occurrence for the Ohio 5/6/7, Wyodak, and North Dakota coal samples},
  author = {Allan Kolker and Stanley J. Mroczkowski and Curtis A. Palmer and Kristen O. Dennen and Robert B. Finkelman and John H. Bullock},
  year = {2002},
  doi = {10.3133/ofr02224},
  url = {https://pubs.usgs.gov/publication/ofr02224},
  note = {Source identifier: ofr02224}
}