L. William Stephenson, ?The larger invertebrate fossils of the Navarro Group of Texas (exclusive of corals and crustaceans and exclusive of the fauna of the Escondido Formation)?, The University of Texas Publication, vol. 4101, pp. 1-641, 1941.

R. A.  Philippi, Handbuch der Conchyliologie und Malacozoologie. Halle: Eduard Anton, 1853, p. 547 [xx].

H. M. D.  de Blainville, ?Mollusques, Mollusca?, in Dictionnaire des Sciences Naturelles, vol. 32, 60 vol., Strasbourg; Paris: F. G. Levrault; Le Normant, 1824, pp. 1-392.

L. William Stephenson, ?The larger invertebrate fossils of the Navarro Group of Texas (exclusive of corals and crustaceans and exclusive of the fauna of the Excondido Formation)?, The University of Texas Publication, vol. 4101, pp. 1-641, 1941.