Frey, R.C. (1995). Middle and Upper Ordovician nautiloid cephalopods of the Cincinnati Arch region of Kentucky, Indiana, and Ohio. U S Geological Survey Professional Paper, 1066-P, P1-P12
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Frey, R.C.
1995
Middle and Upper Ordovician nautiloid cephalopods of the Cincinnati Arch region of Kentucky, Indiana, and Ohio.