Williams et al., 1978

Williams, G.L., Sarjeant, W.A.S. and Kidson, E.J., 1978: A glossary of the terminology applied to dinoflagellate amphiesmae and cysts and acritarchs: 1978 edition. American Association of Stratigraphic Palynologists, Contributions Series, 2A:1-121, pl. 1-15.