	Authors	Year	Title
	Becker	1993	Stratigraphische Gliederung und Ammonoideen-Faunen im Nehdenium (Oberdevon II) von Europa und Nord-Afrika. Courier Forschungsinstitut Senckenberg, 155: 1-405, fig.1-98, pl.1-26; Frankfurt am Main.
	Foord & Crick	1897	Catalogue of the fossil Cephalopoda in the British Museum (Natural History). Part III, containing the Bactritidae and part of the Suborder Ammonoidea). pp.I-XXXIII, 1-303, 145 figs., London.