Reference

J. Alan Holman, Uwe Fritz (2001): A new emydine species from the Middle Miocene (Barstovian) of Nebraska, USA with a new generic arrangement for the species of Clemmys sensu McDowell (1964) (Reptilia: Testudines: Emydidae) – Zoologische Abhandlungen - Staatliches Museum für Tierkunde Dresden – 51: 331 - 353.