Pflaumann and Krasheninnikov, 1978
From dinoflaj3
Pflaumann, U. and Krasheninnikov, V.A., 1978: Cretaceous calcisphaerulids from D.S.D.P. Leg 41, eastern North Atlantic. In: Lancelot, Y. et al., Deep Sea Drilling Project, Washington, Initial Reports, v.41, p.817-839, pl.1-8.