Heilmann-Clausen and Costa, 1989
From dinoflaj3
Heilmann-Clausen, C. and Costa, L.I., 1989: Dinoflagellate zonation of the uppermost Paleocene? to Lower Miocene in the Wursterheide Research Well, NW Germany. Geologisches Jahrbuch, v.111, p.431-521, pl.1-21.