Klapper, Gilbert. “Patrognathus and Siphonodella (Conodonta) from the Kinderhookian (Lower Mississippian) of Western Kansas and Southwestern Nebraska”. Bulletin (Kansas Geological Survey), no. 202, Jan. 1971, pp. 1-14, https://doi.org/10.17161/kgsbulletin.no.i202.22285.