Gini-Newman, Garfield; Graham, Elizabeth (2001). Echoes from the past: world history to the 16th century. Toronto: McGraw-Hill Ryerson Ltd. ISBN9780070887398. OCLC46769716.
Farlow, James Orville; Brett-Surmann, M. K. (1999). The Complete Dinosaur. Bloomington, Indiana: Indiana University Press. p. 15. ISBN9780253213136. OCLC37107117.