@misc{indiciaed8b57f600308,
  title = {Occurrence and morphology of carbonate concretions in the Beulah-Zap coal bed, Williston basin, North Dakota},
  author = {C.W.M. Keighin and R. M. Flores and T. Rowland},
  year = {1996},
  doi = {10.1016/0146-6380(96)00020-4},
  url = {https://pubs.usgs.gov/publication/70019328},
  note = {Source identifier: 70019328}
}