@misc{indiciaeb53e42d5e8f9,
  title = {Early Miocene nonmarine diatoms from the Pine Ridge area, Sioux County, Nebraska},
  author = {G. W. Andrews},
  year = {1971},
  doi = {10.3133/pp683e},
  url = {https://pubs.usgs.gov/publication/pp683E},
  note = {Source identifier: pp683E}
}