Davey et al., 1966
From dinoflaj3
Davey, R.J., Downie, C., Sarjeant, W.A.S. and Williams, G.L., 1966: VII. Fossil dinoflagellate cysts attributed to Baltisphaeridium. In: Davey, R.J., Downie, C., Sarjeant, W.A.S. and Williams, G.L., Studies on Mesozoic and Cainozoic dinoflagellate cysts; British Museum (Natural History) Geology, Bulletin, Supplement 3, p.157-175.