《资治通鉴·汉纪·汉纪十一》
匈奴左贤王率骑兵四万，将李广率领的先头部队团团包围。李广的军士都感到恐惧，李广便命自己的儿子李敢独自率领数十名骑兵直穿敌阵，从敌阵左右冲出后返回。李敢向李广报告说： 匈奴兵很容易对付。 
匈奴左贤王将四万骑围广，广军士皆恐；广乃使其子敢独与数十骑驰贯胡骑，出其左右而还，告广曰： 胡虏易与耳！ 
The Left Worthy King of the Huns led forty thousand horsemen to surround the vanguard led by Li Guang. The soldiers from Li Guang were frightened, so Li Guang ordered his son Li Gan to singlehandedly lead a few dozen cavalrymen straight through the enemy ranks, then from the left and right of the enemy ranks, break out and return. Li Gan reported to Li Guang, saying: "The soldiers of the Huns are very easy to deal with."