	Authors	Year	Title
	Becker	1996	New faunal records and holostratigraphic correlation of the Hasselbachtal D/C-Boundary Auxiliary Stratotype (Germany). Annales Société géologique de Belgique 117 (1994): 19-45, 5 fig., 3 tabl., 3 pls., Bruxelles.
	Korn	1992	Heterochrony in the evolution of Late Devonian Ammonoids. Acta Paleontologica Polonica, 37: 21-36, fig.1-6, tab.1-3; Warszawa.