behavior in pachycephalosaurs (Ornithischia: Dinosauria): a new look at head-butting behavior (pdf). Contributions to Geology. 1997, 32 (1): 19–25 [2007-12-30]
delights its fans. The National. [2021-09-12]. (原始内容存档于2022-12-12). Bull Butting / Bull Fighting, Fujairah - Best time to visit. Trawell.in. [2021-09-12]