@misc{indiciaee9d02bc59298,
  title = {Results of some airborne VLF surveys in northern Wisconsin},
  author = {Frank C. Frischknecht},
  year = {1971},
  doi = {10.3133/ofr71115},
  url = {https://pubs.usgs.gov/publication/ofr71115},
  note = {Source identifier: ofr71115}
}