Tangen et al., 1982
From dinoflaj3
Tangen, K., Brand, L.E., Blackwelder, P.L. and Guillard, R.R.L., 1982: Thoracosphaera heimii (Lohmann) Kamptner is a dinophyte: observations on its morphology and life cycle. Marine Micropaleontology, v.7, p.193-212.