Poulsen and Riding, 1992
From dinoflaj2
Poulsen, N.E. and Riding, J.B., 1992: A revision of the Late Jurassic dinoflagellate cysts Ambonosphaera? staffinensis (Gitmez 1970) comb. nov. and Senoniasphaera jurassica (Gitmez and Sarjeant 1972) Lentin and Williams, 1976. Palynology, v.16, p.25-34, pl.1.
