Yu Duan (2020). The source of the seashells and ivories found in southwest China in the pre-Qin Period. EurASEAA14 Volume I: Ancient and Living Traditions.DOI
Duan Yu (2007). The Di and the Qiang Nationalities in the West Sichuan Plateau in the Historical Periods Prior to the Qin Dynasty. Journal of Aba Teachers College.