@misc{indiciaec4368ffbbb80,
  title = {Amygdule mineral zoning in the Portage Lake lava series, Michigan copper district},
  author = {R.E. Stoiber and Edward S. Davidson},
  year = {1959},
  doi = {10.2113/gsecongeo.54.8.1444},
  url = {https://pubs.usgs.gov/publication/70211566},
  note = {Source identifier: 70211566}
}