Cullers, R.L. and Berendsen, P. 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, (Jul. 1993), 55–72. DOI:https://doi.org/10.17161/cres.v0i235.11784.