Sarjeant and Stancliffe, 1994
From dinoflaj3
Sarjeant, W.A.S. and Stancliffe, R.P.W., 1994: The Micrhystridium and Veryhachium complexes (Acritarcha: Acanthomorphitae and Polygonomorphitae): a taxonomic reconsideration. Micropaleontology, v.40, no.1, p.1-77, pl.1.