Wolf, 1980
From dinoflaj3
Wolf, R., 1980: The lower and upper boundary of the Ordovician System of some selected regions (Celtiberia, eastern Sierra Morena) in Spain. Part I: the Lower Ordovician sequence of Celtiberia. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, v.160, no.1, p.118-137.