Popovsky and Pfiester, 1982
From dinoflaj2
Popovsky, J. and Pfiester, L.A., 1982: The life-histories of Stylodinium sphaera Pascher and Cystodinedria inermis (Geitler) Pascher (Dinophyceae), two freshwater facultative predator-autotrophs. Archiv für Protistenkunde, 125, p.115-127, pl. 1-3.