Harker and Sarjeant, 1975
From dinoflaj3
Harker, S.D. and Sarjeant, W.A.S., 1975: The stratigraphic distribution of organic-walled dinoflagellate cysts in the Cretaceous and Tertiary. Review of Palaeobotany and Palynology, v.20, no.4, p.217-315, pl.1.