@misc{indiciaeb28836f32fc5,
  title = {Industrial minerals deposit models; grade and tonnage models},
  author = {James D. Bliss},
  year = {1992},
  doi = {10.3133/ofr92437},
  url = {https://pubs.usgs.gov/publication/ofr92437},
  note = {Source identifier: ofr92437}
}