@misc{indiciaee0b302117950,
  title = {Diatoms and tonsteins as paleoenvironmental and paleodepositional indicators in a Miocene coal bed, Costa Rica.},
  author = {J. D. Sanchez and J.P. Bradbury and B.F. Bohor and D. A. Coates},
  year = {1987},
  doi = {10.2307/3514643},
  url = {https://pubs.usgs.gov/publication/70014787},
  note = {Source identifier: 70014787}
}