@misc{indiciaee50d2a2d3136,
  title = {Aeromagnetic maps and second vertical derivative maps of Great Sitkin Island, Northern Adak Island, and part of northeastern Umnak Island, Alaska},
  author = {Isidore Zietz and Roland G. Henderson},
  year = {1949},
  doi = {10.3133/ofr499},
  url = {https://pubs.usgs.gov/publication/ofr499},
  note = {Source identifier: ofr499}
}