Cullers, Robert L., and Pieter Berendsen. 1993. “Composition of Rift-Related Igneous and Sedimentary Rocks of the Keweenawan Supergroup in the Poersch No. 1, OZ-1, Finn, and Friederich Wells, Northeastern Kansas”. Current Research in Earth Sciences 235 (July): 55-72. https://doi.org/10.17161/cres.v0i235.11784.