@misc{indiciaeb2d81b36959a,
  title = {Map of part of Iron County, Michigan, showing part of area of aeromagnetic survey and magnetic trend lines; Magnetic maps from ground and airborne surveys of the Mangum, Oklahoma, area},
  author = {L. P. Barrett and F. G. Pardee and W. Osgood and H. E. Hawkes},
  year = {1946},
  doi = {10.3133/gp3},
  url = {https://pubs.usgs.gov/publication/gp3},
  note = {Source identifier: gp3}
}