《汉书·传·匈奴传下》
光禄大夫谷永、议郎杜钦认为 汉朝建立以来，匈奴屡次犯边为害，所以我们才设立封爵位赏金钱的厚遇，招徕投降的匈奴人。
光禄大夫谷永、议郎杜钦以为： 汉兴，匈奴数为边害，故设金爵之赏以待降者。
Guanglu Dafu Gu Yong and Yilang Du Qin believed that since the establishment of the Han Dynasty, the Huns border and caused harm repeatedly. Therefore, we established a noble title and rewarded them with money, to attract the surrendered Huns.