Arkell, W. J., R. C. Moore, A. K. Miller, W. M. Furnish, and O. H. Schindewolf. 1957. “Part L, Mollusca 4, Ch. 3, P. 205-308”. Treatise on Invertebrate Paleontology, January. https://doi.org/10.17161/dt.v0i0.5266.