@misc{indiciae3d384699e3e6,
  title = {Mineral resources of Alaska, report on progress of investigations in 1917--Sulphur on Unalaska and Akun islands and near Stepovak Bay},
  author = {A.G. Maddren},
  year = {1919},
  doi = {10.3133/b692e},
  url = {https://pubs.usgs.gov/publication/b692E},
  note = {Source identifier: b692E}
}