@misc{indiciae25280de5bbf2,
  title = {Nonopaque heavy minerals in sandstone of Jurassic and Cretaceous age in the Black Hills, Wyoming and South Dakota},
  author = {W. J. Mapel and Wayne A. Chisholm and Richard E. Bergenback},
  year = {1964},
  doi = {10.3133/b1161c},
  url = {https://pubs.usgs.gov/publication/b1161C},
  note = {Source identifier: b1161C}
}