@misc{indiciaeed277d795442,
  title = {Notes on the geology and iron cores of the Cuyuna district, Minnesota},
  author = {E.C. Harder and A.W. Johnston},
  year = {1918},
  doi = {10.3133/b660a},
  url = {https://pubs.usgs.gov/publication/b660A},
  note = {Source identifier: b660A}
}