Korn, Dieter, and Jürgen Bockwinkel. 2022. “The Early Gephuroceratid Ammonoids from the Roteisenstein Formation of Dillenburg (Cephalopoda, Ammonoidea)”. European Journal of Taxonomy 823 (1):10-47. https://doi.org/10.5852/ejt.2022.823.1811.