Hedlund and Norris, 1986
From dinoflaj2
Hedlund, R.W. and Norris, G., 1986: Dinoflagellates cyst assemblage from Middle Albian strata of Marshall County, Oklahoma, U.S.A. Review of Palaeobotany and Palynology, v.46, p.293-309, pl.1-3.
