Citation: R. Crowther P et M. Bergstrom S, Cortical bandages in an upper Ordovician Glyptograptid graptolite from Ohio, Bollettino della Societa paleontologica italiana , 19(02), 1980, pp. 250-253
Citation: E. Mitchell C et M. Bergstrom S, Three-dimensionally preserved Richmondian Graptolites from southwestern Ohio and the Graptolites Correlation of the north American Upper Ordovician Standard, Bollettino della Societa paleontologica italiana , 16(02), 1977, pp. 257-270