Cramer and Diez, 1972
From dinoflaj2
Cramer, F.H. and Diez, M.del C. R., 1972: North American Silurian palynofacies and their spatial arrangement: acritarchs. Palaeontographica, Abteilung B, v.138, no.5-6, p.107-180, pl.31-36.
