Korn, D., and J. Bockwinkel. “The Pharciceratid Ammonoids from the Roteisenstein Formation of Dillenburg (Cephalopoda, Ammonoidea)”. European Journal of Taxonomy, vol. 771, no. 1, Sept. 2021, pp. 1-79, doi:10.5852/ejt.2021.771.1503.