@misc{indiciae1fd65ef0ed4b,
  title = {Collection, chemical analysis, and evaluation of coal samples in 1975},
  author = {Vernon Emanuel Swanson and J.H. Medlin and J. R. Hatch and S.L. Coleman and G.H. Wood and S.D. Woodruff and R.T. Hildebrand},
  year = {1976},
  doi = {10.3133/ofr76468},
  url = {https://pubs.usgs.gov/publication/ofr76468},
  note = {Source identifier: ofr76468}
}