Pennsylvanian cephalopods of Ohio. Part 1, Nautiloid and bactritoid cephalopods,By Myron T. Sturgeon, Delbert L. Windle, Royal H. Mapes, and Richard D. Hoare; Part 2, Ammonoid cephalopods, by Royal H. Mapes, Delbert L. Windle, Myron T. Sturgeon, and Richard D. Hoare. 260 p., 45 figs., 34 tables, 54 pls., 1997.