Reference

Armin Scherzinger, Günter Schweigert, Horacio Parent (2008): Sexual phenomena in Late Jurassic Aspidoceratidae (Ammonoidea). Dimorphic correspondence between Physodoceras hermanni (Berckhemer) and Sutneria subeumela Schneid, and first record of possible hermaphroditism – Palaeodiversity – 1: 181 - 187.