@misc{indiciae2f506f8dab26,
  title = {Petrology and chemistry of Permian coals from the Paraná Basin: 1. Santa Terezinha, Leão-Butiá and Candiota Coalfields, Rio Grande do Sul, Brazil},
  author = {W. Kalkreuth and M. Holz and M. Kern and G. Machado and A. Mexias and M.B. Silva and J. Willett and R. Finkelman and H. Burger},
  year = {2006},
  doi = {10.1016/j.coal.2005.10.006},
  url = {https://pubs.usgs.gov/publication/70028288},
  note = {Source identifier: 70028288}
}