《资治通鉴·汉纪·汉纪五十五》
曹操大喜，于是留下曹洪、荀攸防守大营，亲自率领五千名步骑兵出击。军队一律用袁军的旗号，兵士嘴里衔着小木棍，把马嘴绑上，以防发出声音，夜里从小道出营，每人抱一捆柴草。经过的路上遇到有人盘问，就回答说： 袁公恐怕曹操袭击后方辎重，派兵去加强守备。 
操大喜，乃留曹洪、荀攸守营，自将步骑五千人，皆用袁军旗帜，衔枚缚马口，夜从间道出，人抱束薪，所历道有问者，语之曰： 袁公恐曹操钞略后军，遣军以益备。 
Cao Cao was overjoyed, and so he left Cao Hong, Xun You to defend the camp, and personally led five thousand men of infantry and cavalry to attack. The army all use Yuan's army's flags, the soldiers hold small wooden sticks in their mouths, and tie up the horses' mouths, to prevent making any sound, and go out of the camp through the trails at night, each carrying a bundle of firewood. On the way, they met someone who questioned them, they replied: Duke Yuan is afraid that Cao Cao will attack the rear baggage, so he sent troops to strengthen the defenses.