References:

Bralower, T. J. & Bergen, J. A. (1998). Cenomanian-Santonian calcareous nannofossil biostratigraphy of a transect of cores drilled across the Western Interior Seaway. In, Dean, W. E. & Arthur, M. A. (eds) Stratigraphy and paleoenvironments of the Cretaceous Western Interior Seaway. SEPM Concepts in Sedimentology and Paleontology. -. gs :: ::

Bukry, D. (1969). Upper Cretaceous coccoliths from Texas and Europe. The University of Kansas Paleontological Contributions. Article 51 (Protista 2): 1-79. gs :: ::

Crux, J. A. (1989). Biostratigraphy and palaeogeographical applications of Lower Cretaceous nannofossils from north-western Europe. In, Crux, J. A. & van Heck, S. E. (eds) Nannofossils and their applications. British Micropalaeontological Society Publication Series. 143-211. gs :: ::

Gartner, S. (1968). Coccoliths and related calcareous nannofossils from Upper Cretaceous deposits of Texas and Arkansas. The University of Kansas Paleontological Contributions. Article 48 (Protista 1): 1-56. gs :: ::