Khowaja-Ateequzzaman et al., 1990
From dinoflaj3
Khowaja-Ateequzzaman, Garg, R. and Jain, K.P., 1990: Observations on archaeopyle type in fossil dinoflagellate cyst species Dingodinium cerviculum Cookson and Eisenack 1958. The Palaeobotanist, v.37, no.6, p.267-277, pl.1-2.