↑Gray,J.E. (1873) Additional notes on the form of the bones in the sternum of very young tortoises, and their development., Ann. Mag. Nat. Hist. (4) 12: 319-323
↑ 3.03.1Gray, J. E. (1831) A synopsis of the species of Class Reptilia. In: Griffith, E & E. Pidgeon: The animal kingdom arranged in conformity with its organisation by the Baron Cuvier with additional descriptions of all the species hither named, and of many before noticed [Vol. 9, Whittaker, Treacher and Co., London: 481 + 110 pp.