G. Kuhlmann; C.G. Langereis; D. Munsterman; R.-J. van Leeuwen; R. Verreussel; J.E. Meulenkamp; Th.E. Wong. Integrated Chronostratigraphy of the Pliocene-Pleistocene Interval and Its Relation to the Regional Stratigraphical Stages in the Southern North Sea Region. njg 2006, 85, 19 - 35.