@misc{indiciaebb7c7be24b16,
  title = {Iron and manganese},
  author = {E. F. Burchard and A.C. Spencer and W. C. Phalen},
  year = {1908},
  doi = {10.3133/b340e},
  url = {https://pubs.usgs.gov/publication/b340E},
  note = {Source identifier: b340E}
}