《汉书·传·匈奴传上》
当时一个雁门尉史巡逻防地，发现敌人，便去保卫这个哨所，单于抓住了他，想杀他。
时雁门尉史行徼，见寇，保此亭，单于得，欲刺之。
At that time, a gatekeeper of Yanmen was patrolling the defense area and found the enemy, so he went to defend the outpost. Shanyu captured him and wanted to kill him.