《史记·十二本纪·孝文本纪》
六月，皇帝说： 汉朝和匈奴结为兄弟，不让它侵害边境，为此输送匈奴的礼物非常丰厚。
六月，帝曰： 汉与匈奴约为昆弟，毋使害边境，所以输遗匈奴甚厚。
In the sixth month, the Emperor said: The Han Dynasty and the Xiongnu have become brothers, and do not allow them to invade the border, so the gifts sent to the Xiongnu are very generous.