Morey, G. B. (February 1999). "High-grade iron ore deposits of the Mesabi Range, Minnesota; product of a continental-scale Proterozoic ground-water flow system". Economic Geology. 94 (1): 133–42. Bibcode:1999EcGeo..94..133M. doi:10.2113/gsecongeo.94.1.133.
harvard.edu
ui.adsabs.harvard.edu
Morey, G. B. (February 1999). "High-grade iron ore deposits of the Mesabi Range, Minnesota; product of a continental-scale Proterozoic ground-water flow system". Economic Geology. 94 (1): 133–42. Bibcode:1999EcGeo..94..133M. doi:10.2113/gsecongeo.94.1.133.
Black, Robert F. (2005). "Chapter 10: St. Croix Dalles Interstate Park". Geology of Ice Age National Scientific Reserve of Wisconsin, NPS Scientific Monograph No. 2. National Park Service. Archived from the original on 2007-05-13. Retrieved 2007-06-30.
"Map". Wetlands Component Assessment Regions. National Resources Conservation Service, United States Department of Agriculture. Archived from the original on 2007-03-14. Retrieved 2007-06-30.
usgs.gov
vulcan.wr.usgs.gov
"Minnesota". America’s Volcanic Past: Places. U.S. Geological Survey, Cascades Volcanic Observatory. Archived from the original on 2009-01-10. Retrieved 2007-06-30.
Townsend, Catherine L.; John T. Figge (2002). "Dance of the Giant Continents". Northwest Origins. Burke Museum of History and Culture, University of Washington. Retrieved 2007-04-02.
web.archive.org
"Minnesota". America’s Volcanic Past: Places. U.S. Geological Survey, Cascades Volcanic Observatory. Archived from the original on 2009-01-10. Retrieved 2007-06-30.
"Map". Wetlands Component Assessment Regions. National Resources Conservation Service, United States Department of Agriculture. Archived from the original on 2007-03-14. Retrieved 2007-06-30.
Black, Robert F. (2005). "Chapter 10: St. Croix Dalles Interstate Park". Geology of Ice Age National Scientific Reserve of Wisconsin, NPS Scientific Monograph No. 2. National Park Service. Archived from the original on 2007-05-13. Retrieved 2007-06-30.