E. G.  Kauffman, Sageman, B. B., Kirkland, J. I., Elder, W. P., Harries, P. J., and Villamil, T., ?Molluscan biostratigraphy of the Cretaceous Western Interior Basin, North America?, in Evolution of the Western Interior Basin. Geological Association of Canada Special Paper, vol. 39, W. G. E.  Caldwell and Kauffman, E. G., Eds. 1993, pp. 397-434.

E. G.  Kauffman, Sageman, B. B., Kirkland, J. I., Elder, W. P., Harries, P. J., and Villamil, T., ?Molluscan biostratigraphy of the Cretaceous Western Interior Basin, North America?, in Evolution of the Western Interior Basin. Geological Association of Canada Special Paper, vol. 39, W. G. E.  Caldwell and Kauffman, E. G., Eds. 1993, pp. 397-434.