@misc{indiciae74a457b56abd,
  title = {Grade and tonnage model for tungsten skarn deposits—2020 update},
  author = {Carlin J. Green and Graham W. Lederer and Heather L. Parks and Michael L. Zientek},
  year = {2020},
  doi = {10.3133/sir20205085},
  url = {https://pubs.usgs.gov/publication/sir20205085},
  note = {Source identifier: sir20205085}
}