^Wright, C. W. with Callomon, J.H. and Howarth, M.K. (1996), Mollusca 4 Revised, Cretaceous Ammonoidea, vol. 4, in Treatise on Invertebrate Paleontology, Part L (Roger L. Kaesler et el. eds.), Boulder, Colorado: The Geological Society of America & Lawrence, Kansas: University of Kansas Press, 67-111.