morphology
Nesom, G. 1978. Erigeron hessii sp. nov. and Erigeron kuschei Eastwood (Compositae), two closely related narrow endemics from the southwestern United States. Brittonia 30(4): 440-446.
Clench, W.J. and R.D. Turner. 1956. Freshwater mollusks of Alabama, Georgia, and Florida from the Escambia to the Suwanee River. Bulletin of the Florida State Museum Biological Sciences, 1(3): 97-239.
Hershler, R.H., H.-S. Liu, and C.A. Stockwell. 2002. A new genus and species of aquatic gastropods (Rissooidea: Hydrobiidae) from the North American southwest: phylogenetic relationships and biogeography. Proceedings of the Biological Society of Washingto
Hershler, R.H. 2001. Systematics of the North and Central American aquatic snail genus Tryonia (Rissooidea: Hydrobiidae). Smithsonian Contributions to Zoology, 612: 1-53.