(1)
Sawin, R. S.; Franseen, E. K.; West, R. R.; Ludvigson, G. A.; Watney, W. L. Clarification and Changes in Permian Stratigraphic Nomenclature in Kansas. CRES 2008, No. 254, 1-4. https://doi.org/10.17161/cres.v0i254.11839.