Ciesielski, P. F.; Bjorklund, K. R. (1995): Ecology, morphology, stratigraphy, and the paleoceanographic significance of Cycladophora davisiana davisiana; Part II, Stratigraphy in the North Atlantic (DSDP Site 609) and Labrador Sea (ODP Site 646B). Elsevier, Amsterdam, Netherlands, Marine Micropaleontology, 25 (1), 67-86, georefid:1996-005785