@misc{indiciae8973a9ab6ace,
  title = {Element concentrations toxic to plants, animals, and man},
  author = {L. P. Gough and Hansford Threlkeld Shacklette and Arthur A. Case},
  year = {1979},
  doi = {10.3133/b1466},
  url = {https://pubs.usgs.gov/publication/b1466},
  note = {Source identifier: b1466}
}