《汉书·传·李广苏建传》
过了五六年，单于的弟弟于轩王下海打猎，因苏武会制做猎网和箭缴，校正弓弩，于轩王很喜欢他，送给他衣服和食物。
积五、六年，单于弟於靬王弋射海上。武能网纺缴，檠弓弩，於靬王爱之，给其衣食。
After five or six years, the Chanyu's younger brother Yu Xuanwang went to the sea to hunt. Because Su Wu knew how to make hunting nets and arrows, and how to adjust bows and crossbows, Yu Xuanwang liked him very much and gave him clothes and food.