@misc{indiciae69bf4ce2bae3,
  title = {Aeromagnetic map of parts of the Ralph and Norway quadrangles, Dickinson County, Michigan},
  author = {Members of the Engineering Geology and Ground Water Branches, U.S. Geological Survey},
  year = {1967},
  doi = {10.3133/gp610},
  url = {https://pubs.usgs.gov/publication/gp610},
  note = {Source identifier: gp610}
}