1. Molnar, R. E., Kurzanov, S. M. & Dong, Z. in The Dinosauria (eds Weishampel, D. B., Dodson, P. & Osmolska, H.) 169–209 (Univ. California Press, Berkeley, 1990).
2. Carpenter, K. in Aspects of Nonmarine Cretaceous Geology (eds Mateer, N. J. & Chen, P. J.) 250–268 (China Ocean Press, Beijing, 1992).
3. Holtz, T. R. J. Paleont 68, 1100–1117 (1994).
4. Gilmore, C. W. Bull. Am. Mus. nat. Hist. 67, 23–78 (1933).
5. Mader, B. J. & Bradley, R. L. J. vert. Paleont. 9, 41–55 (1989).