@misc{indiciaebc0325a7800d,
  title = {Natural gamma aeroradioactivity map of the Minneapolis-Saint Paul area, Minnesota-Wisconsin},
  author = {S.K. Neuschel},
  year = {1969},
  doi = {10.3133/gp658},
  url = {https://pubs.usgs.gov/publication/gp658},
  note = {Source identifier: gp658}
}