Magnetostratigraphy and geochronology of the Hell Creek and basal Fort Union Formations of southwestern North Dakota and a recalibration of the age of the Cretaceous-Tertiary boundaryDOI: info:10.1130/0-8137-2361-2.35v. 361Geological Society of America35–55
Hicks, Jason F., Johnson, Kirk R., Obradovich, John D., Tauxe, Lisa, and Clark, David. 2002. "Magnetostratigraphy and geochronology of the Hell Creek and basal Fort Union Formations of southwestern North Dakota and a recalibration of the age of the Cretaceous-Tertiary boundary." In The Hell Creek Formation and the Cretaceous-Tertiary boundary in the northern Great Plains: An Integrated continental record of the end of the Cretaceous ; Special Paper 361. Hartman, Joseph H., Johnson, Kirk R., and Nichols, Douglas J., editors. 35–55. Geological Society of America. 361 https://doi.org/10.1130/0-8137-2361-2.35.