18.
Davey, R.J., Williams, G.L., 1966. V. The genus Hystrichosphaeridium and its allies. In: Davey, R.J., Downie, C., Sarjeant, W.A.S., Williams, G.L. (eds), Studies on Mesozoic and Cainozoic dinoflagellate cysts. British Museum (Natural History) Geology, Bulletin, Supplement 3, 53–106.