《汉书·传·卫青霍去病传》
后来捉到俘虏，俘虏说单于在束面，于是皇帝改令霍去病从代郡出发，令卫青从定襄出发。
捕虏，虏言单于东，乃更令去病出代郡，令青出定襄。
Later, they captured a prisoner, who said that the Chanyu was at Shumian, so the emperor changed his order and instructed Huo Qubing to set off from Daijun, and Wei Qing from Dingxiang.