Ioannides et al., 1977
From dinoflaj3
Ioannides, N.S., Stavrinos, G.N. and Downie, C., 1977: Kimmeridgian microplankton from Clavell's Hard, Dorset, England. Micropaleontology, v.22, no.4, p.443-478, pl.1-5. (Cover date 1976, issue date 1977, according to Ioannides, 1986, p.46.)