Harland and Hill, 1979
From dinoflaj3
Harland, R. and Hill, J., 1979: A reappraisal of the Cainozoic dinoflagellate cyst "Hystrichosphaeridium" choanophorum Deflandre et Cookson 1955. Review of Palaeobotany and Palynology, v.28, p.37-45, pl.1-2.