Tài liệu tham khảo WikiPedia: Hypacrosaurus http://nature.ca/notebooks/english/hypacro.htm http://digitallibrary.amnh.org/dspace/handle/2246/... //doi.org/10.1671%2F039.029.0405 http://internt.nhm.ac.uk/jdsml/nature-online/dino-...