Dietze V., Franz M., Dietl G. (2010) Ammoniten aus dem Übergangsbereich Ovale-/Laeviuscula-Zone (Unter-Bajocium) des Unteren Wedelsandsteins von Zillhausen (Westalb, Süddeutschland) // Jh. Ges. Naturkde. Württemberg. Bd. 166. S. 23–30. Pdf: http://rogov.zwz.ru/Dietze%20et%20al,2010_Unter-Bajocium.pdf
An ammonite fauna with Sonninia sp., Otoites cf. fortis, Witchellia jugifera and W. cf. jugifera is described from the boundary region of the Ovale and Laeviuscula Zones at the Roschbach creek near Balingen (Western Swabian Alb).
thanks to Volker Dietze for this pdf!
