@misc{indiciaeef10d3ba33ee,
  title = {Assessment of geochemical variability and a listing of geochemical data for surface soils of eastern North Dakota and parts of northeastern South Dakota and northwestern Minnesota},
  author = {R. C. Severson and S. A. Wilson},
  year = {1990},
  doi = {10.3133/ofr90310},
  url = {https://pubs.usgs.gov/publication/ofr90310},
  note = {Source identifier: ofr90310}
}