@misc{indiciaee26bafcba98c,
  title = {Isopach and structure contour mapping of thin bentonite and shale beds in an area of mapped lineaments, central South Dakota},
  author = {A.F. Chleborad},
  year = {1986},
  doi = {10.3133/ofr86414},
  url = {https://pubs.usgs.gov/publication/ofr86414},
  note = {Source identifier: ofr86414}
}