Reference
Larisa A. Doguzhaeva, Royal H. Mapes, H. Mutvei (2002): Shell Morphology and Ultrastructure of the Early Carboniferous Coleoid Hematites FLOWER & GORDON, 1959 (Hematitida ord.nov) from Midcontinent (USA) – Abhandlungen der Geologischen Bundesanstalt in Wien – 57: 299 - 320.