Evitt et al., 1967
From dinoflaj3
Evitt, W.R., Clarke, R.F.A. and Verdier, J.-P., 1967: Dinoflagellate studies III. Dinogymnium acuminatum n. gen., n.sp. (Maastrichtian) and other fossils formerly referable to Gymnodinium Stein. Stanford University Publications, Geological Sciences, v.10, no.4, p.1-27, pl.1-3.