Hell Creek Formation: A 2001 synthesisDOI: info:10.1130/0-8137-2361-2.503v. 361Geological Society of America503–510
Johnson, Kirk R., Nichols, Douglas J., and Hartman, Joseph H. 2002. "Hell Creek Formation: A 2001 synthesis." 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 Papers 361. Hartman, Joseph J., Johnson, Kirk R., and Nichols, Douglas J., editors. 503–510. Geological Society of America. 361 https://doi.org/10.1130/0-8137-2361-2.503.