《北史·列传·卷八十四》
终宣武世到正光，牦牛、蜀马和西南的珍宝，无一年不送。
终宣武世至于正光，嫠牛、蜀马及西南之珍，无岁不至。
From the time of Emperor Xuanwu to that of Zhengguang, the yak, Sichuan horses and the treasures of Southwest were sent to the Court every year.