Robaszynski et al., 1985
From dinoflaj3
Robaszynski, F., Bless, M.J.M., Felder, P.J., Foucher, J.-C., Legoux, O., Manivit, H., Meesen, J.P.M.T. and van der Tuuk, L.A., 1985: The Campanian-Maastrichtian boundary in the chalky facies close to the type-Maastrichtian area. Bulletin des Centres de recherches exploration-production Elf-Aquitaine, v.9, no.1, p.1-113, pl.1-22.