《北史·列传·卷八十七》
薛举、窦建德、王世充、刘武周、梁师都、李轨、高开道之类，虽然都超越名分，自加尊号，但都对始毕称臣，接受可汗的称号。使者来来往往，路上不断。
薛举、窦建德、王世充、刘武周、梁师都、李轨、高开道之徒，虽僭尊号，皆称臣，受其可汗之号，使者往来，相望于道。
Xue Ju, Dou Jiande, Wang Shichong, Liu Wuzhou, Liang Shidu, Li Gui, and Gao Kaidao, although they all surpassed their ranks and gave themselves honorary titles, all declared themselves subjects of Shibi and accepted the title of Khan. Messengers came and went, and the road was constantly crowded.