Authors Year Title
Bisat 1924 The Carboniferous goniatites of the North of England and their zones.
Proceedings of the Yorkshire Geological Society, 20: 40-124, pl.1-10; Leeds.
Bouckaert 1960a Stratigraphie et palóntologie de la super-zone R1 dans les vallées de la Berwinne et de la Geule.
Mémoires Inst. Géol. Univ. Louvain, 21: 3-94, fig.A-E, tab.1-2, pl.1-5; Louvain.
Bouckaert 1961 Les goniatites du Carbonifère belge.
Docum. Étude Paléontol. Terrain Hooullier: 1-9, pl.1-27; Bruxelles.
Korn 1997 The Palaeozoic ammonoids of the South Portuguese Zone.
Memórias do Instituto geológico e Mineiro 33: 1-131, 69 text-figs., 16 pls., Lisboa.
Patteisky & Schönwälder 1960 Das tiefere Namur nördlich von Wuppertal.
Fortschritte in der Geologie von Rheinland und Westfalen, 3,1: 343-368, fig.1-4, pl.1-4; Krefeld.
Ruan & Zhou 1987 Carboniferous cephalopods in Ningxia Hui Autonomous Region. [In Chinese, with Engl. summary].
Namurian Strata and Fossils of Ningxia, China: 55-177, 78 text-figs., 15 pls., Nanjing.