Plummer, Norman, Ada Swineford, Russell T. Runnels, and John A. Schleicher. “Chemical, Petrographic, and Ceramic Properties of Four Clays from the Dakota Formation in Kansas”. Bulletin (Kansas Geological Survey), no. 109 (January 1, 1954): 161–209. Accessed December 31, 2025. https://journals.ku.edu/kgsbulletin/article/view/22091.