Prince et al., 2008
From dinoflaj3
Prince, I.M., Jarvis, I., Pearce, M.A. and Tocher, B.A., 2008: Dinoflagellate cyst biostratigraphy of the Coniacian-Santonian (Upper Cretaceous): New data from the English Chalk. Review of Palaeobotany and Palynology, v.150, p.59-96, pl.1-2.