Abbink et al., 2001
From dinoflaj3
Abbink, O.A., Callomon, J.H., Riding, J.B., Williams, P.D.B. and Wolfard, A., 2001: Biostratigraphy of Jurassic-Cretaceous boundary strata in the Terschelling Basin, The Netherlands. Proceedings of the Yorkshire Geological Society, v.53, pt.4, p.275-302.