Erkmen and Sarjeant, 1980
From dinoflaj3
Erkmen, U. and Sarjeant, W.A.S., 1980: Dinoflagellate cysts, acritarchs and tasmanitids from the uppermost Callovian of England and Scotland: with a reconsideration of the "Xanthidium pilosum" problem. Geobios, Lyon, no.13 (1), p.45-99, pl.1-8.